diff --git a/TickAPI/TickAPI.Tests/Customers/Services/CustomerServiceTests.cs b/TickAPI/TickAPI.Tests/Customers/Services/CustomerServiceTests.cs
index 9a3eb79..07acc53 100644
--- a/TickAPI/TickAPI.Tests/Customers/Services/CustomerServiceTests.cs
+++ b/TickAPI/TickAPI.Tests/Customers/Services/CustomerServiceTests.cs
@@ -71,6 +71,34 @@ public async Task CreateNewCustomerAsync_WhenCustomerWithUniqueEmail_ShouldRetur
         Assert.Equal(createdAt, result.Value!.CreationDate);
         Assert.Equal(id, result.Value!.Id);
     }
+    
+    [Fact]
+    public async Task CreateNewCustomerAsync_WhenLastNameIsNull_ShouldReturnNewCustomer()
+    {
+        const string email = "new@customer.com";
+        const string firstName = "First";
+        const string lastName = null;
+        Guid id = Guid.NewGuid();
+        DateTime createdAt = new DateTime(1970, 1, 1, 8, 0, 0, DateTimeKind.Utc);
+        var dateTimeServiceMock = new Mock<IDateTimeService>();
+        dateTimeServiceMock.Setup(m => m.GetCurrentDateTime()).Returns(createdAt);
+        var customerRepositoryMock = new Mock<ICustomerRepository>();
+        customerRepositoryMock.Setup(m => m.GetCustomerByEmailAsync(email)).ReturnsAsync(Result<Customer>.Failure(StatusCodes.Status404NotFound, $"customer with email '{email}' not found"));
+        customerRepositoryMock
+            .Setup(m => m.AddNewCustomerAsync(It.IsAny<Customer>()))
+            .Callback<Customer>(c => c.Id = id)
+            .Returns(Task.CompletedTask);
+        var sut = new CustomerService(customerRepositoryMock.Object, dateTimeServiceMock.Object);
+
+        var result = await sut.CreateNewCustomerAsync(email, firstName, lastName);
+        
+        Assert.True(result.IsSuccess);
+        Assert.Equal(email, result.Value!.Email);
+        Assert.Equal(firstName, result.Value!.FirstName);
+        Assert.Equal(lastName, result.Value!.LastName);
+        Assert.Equal(createdAt, result.Value!.CreationDate);
+        Assert.Equal(id, result.Value!.Id);
+    }
 
     [Fact]
     public async Task CreateNewCustomerAsync_WhenCustomerWithNotUniqueEmail_ShouldReturnFailure()
diff --git a/TickAPI/TickAPI.Tests/Organizers/Services/OrganizerServiceTests.cs b/TickAPI/TickAPI.Tests/Organizers/Services/OrganizerServiceTests.cs
index 769ee7f..1e91aa9 100644
--- a/TickAPI/TickAPI.Tests/Organizers/Services/OrganizerServiceTests.cs
+++ b/TickAPI/TickAPI.Tests/Organizers/Services/OrganizerServiceTests.cs
@@ -112,6 +112,50 @@ public async Task CreateNewOrganizerAsync_WhenOrganizerDataIsValid_ShouldReturnN
         Assert.False(result.Value!.IsVerified);
         Assert.Equal(currentDate, result.Value!.CreationDate);
     }
+    
+    [Fact]
+    public async Task CreateNewOrganizerAsync_WhenLastNameIsNull_ShouldReturnNewOrganizer()
+    {
+        // Arrange
+        Guid id = Guid.NewGuid();
+        const string email = "example@test.com";
+        const string firstName = "First";
+        const string lastName = null;
+        const string displayName = "Display";
+        DateTime currentDate = new DateTime(1970, 1, 1, 8, 0, 0, DateTimeKind.Utc);
+
+        var organizerRepositoryMock = new Mock<IOrganizerRepository>();
+        organizerRepositoryMock
+            .Setup(m => m.GetOrganizerByEmailAsync(email))
+            .ReturnsAsync(Result<Organizer>.Failure(StatusCodes.Status404NotFound, $"organizer with email '{email}' not found"));
+        organizerRepositoryMock
+            .Setup(m => m.AddNewOrganizerAsync(It.IsAny<Organizer>()))
+            .Callback<Organizer>(o => o.Id = id)
+            .Returns(Task.CompletedTask);
+        
+        var dateTimeServiceMock = new Mock<IDateTimeService>();
+        dateTimeServiceMock
+            .Setup(m => m.GetCurrentDateTime())
+            .Returns(currentDate);
+        
+        var sut = new OrganizerService(
+            organizerRepositoryMock.Object,
+            dateTimeServiceMock.Object
+        );
+
+        // Act
+        var result = await sut.CreateNewOrganizerAsync(email, firstName, lastName, displayName);
+
+        // Assert
+        Assert.True(result.IsSuccess);
+        Assert.Equal(id, result.Value!.Id);
+        Assert.Equal(email, result.Value!.Email);
+        Assert.Equal(firstName, result.Value!.FirstName);
+        Assert.Equal(lastName, result.Value!.LastName);
+        Assert.Equal(displayName, result.Value!.DisplayName);
+        Assert.False(result.Value!.IsVerified);
+        Assert.Equal(currentDate, result.Value!.CreationDate);
+    }
 
     [Fact]
     public async Task CreateNewOrganizerAsync_WhenWithNotUniqueEmail_ShouldReturnFailure()
diff --git a/TickAPI/TickAPI/Customers/Models/Customer.cs b/TickAPI/TickAPI/Customers/Models/Customer.cs
index 8a78532..5a3c194 100644
--- a/TickAPI/TickAPI/Customers/Models/Customer.cs
+++ b/TickAPI/TickAPI/Customers/Models/Customer.cs
@@ -7,7 +7,7 @@ public class Customer
     public Guid Id { get; set; }
     public string Email { get; set; }
     public string FirstName { get; set; }
-    public string LastName { get; set; }
+    public string? LastName { get; set; }
     public DateTime CreationDate { get; set; }
     public ICollection<Ticket> Tickets { get; set; }    
 }
\ No newline at end of file
diff --git a/TickAPI/TickAPI/Migrations/20250401224843_NullableLastNames.Designer.cs b/TickAPI/TickAPI/Migrations/20250401224843_NullableLastNames.Designer.cs
new file mode 100644
index 0000000..f5bf758
--- /dev/null
+++ b/TickAPI/TickAPI/Migrations/20250401224843_NullableLastNames.Designer.cs
@@ -0,0 +1,357 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Metadata;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using TickAPI.Common.TickApiDbContext;
+
+#nullable disable
+
+namespace TickAPI.Migrations
+{
+    [DbContext(typeof(TickApiDbContext))]
+    [Migration("20250401224843_NullableLastNames")]
+    partial class NullableLastNames
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "9.0.2")
+                .HasAnnotation("Relational:MaxIdentifierLength", 128);
+
+            SqlServerModelBuilderExtensions.UseIdentityColumns(modelBuilder);
+
+            modelBuilder.Entity("CategoryEvent", b =>
+                {
+                    b.Property<Guid>("CategoriesId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<Guid>("EventsId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.HasKey("CategoriesId", "EventsId");
+
+                    b.HasIndex("EventsId");
+
+                    b.ToTable("CategoryEvent");
+                });
+
+            modelBuilder.Entity("TickAPI.Addresses.Models.Address", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<string>("City")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("Country")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<long?>("FlatNumber")
+                        .HasColumnType("bigint");
+
+                    b.Property<long?>("HouseNumber")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("PostalCode")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("Street")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Addresses");
+                });
+
+            modelBuilder.Entity("TickAPI.Admins.Models.Admin", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<string>("Email")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("Login")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Admins");
+                });
+
+            modelBuilder.Entity("TickAPI.Categories.Models.Category", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<string>("CategoryName")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Categories");
+                });
+
+            modelBuilder.Entity("TickAPI.Customers.Models.Customer", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime>("CreationDate")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("Email")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("FirstName")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("LastName")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Customers");
+                });
+
+            modelBuilder.Entity("TickAPI.Events.Models.Event", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<Guid>("AddressId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<string>("Description")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<DateTime>("EndDate")
+                        .HasColumnType("datetime2");
+
+                    b.Property<int>("EventStatus")
+                        .HasColumnType("int");
+
+                    b.Property<long?>("MinimumAge")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<Guid>("OrganizerId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime>("StartDate")
+                        .HasColumnType("datetime2");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("AddressId");
+
+                    b.HasIndex("OrganizerId");
+
+                    b.ToTable("Events");
+                });
+
+            modelBuilder.Entity("TickAPI.Organizers.Models.Organizer", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime>("CreationDate")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("DisplayName")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("Email")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("FirstName")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<bool>("IsVerified")
+                        .HasColumnType("bit");
+
+                    b.Property<string>("LastName")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Organizers");
+                });
+
+            modelBuilder.Entity("TickAPI.TicketTypes.Models.TicketType", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime>("AvailableFrom")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("Currency")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("Description")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<Guid>("EventId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<long>("MaxCount")
+                        .HasColumnType("bigint");
+
+                    b.Property<decimal>("Price")
+                        .HasColumnType("decimal(18,2)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("EventId");
+
+                    b.ToTable("TicketTypes");
+                });
+
+            modelBuilder.Entity("TickAPI.Tickets.Models.Ticket", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<bool>("ForResell")
+                        .HasColumnType("bit");
+
+                    b.Property<string>("NameOnTicket")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<Guid>("OwnerId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<string>("Seats")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<Guid>("TypeId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("OwnerId");
+
+                    b.HasIndex("TypeId");
+
+                    b.ToTable("Tickets");
+                });
+
+            modelBuilder.Entity("CategoryEvent", b =>
+                {
+                    b.HasOne("TickAPI.Categories.Models.Category", null)
+                        .WithMany()
+                        .HasForeignKey("CategoriesId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("TickAPI.Events.Models.Event", null)
+                        .WithMany()
+                        .HasForeignKey("EventsId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("TickAPI.Events.Models.Event", b =>
+                {
+                    b.HasOne("TickAPI.Addresses.Models.Address", "Address")
+                        .WithMany()
+                        .HasForeignKey("AddressId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("TickAPI.Organizers.Models.Organizer", "Organizer")
+                        .WithMany("Events")
+                        .HasForeignKey("OrganizerId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Address");
+
+                    b.Navigation("Organizer");
+                });
+
+            modelBuilder.Entity("TickAPI.TicketTypes.Models.TicketType", b =>
+                {
+                    b.HasOne("TickAPI.Events.Models.Event", "Event")
+                        .WithMany("TicketTypes")
+                        .HasForeignKey("EventId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Event");
+                });
+
+            modelBuilder.Entity("TickAPI.Tickets.Models.Ticket", b =>
+                {
+                    b.HasOne("TickAPI.Customers.Models.Customer", "Owner")
+                        .WithMany("Tickets")
+                        .HasForeignKey("OwnerId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("TickAPI.TicketTypes.Models.TicketType", "Type")
+                        .WithMany("Tickets")
+                        .HasForeignKey("TypeId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Owner");
+
+                    b.Navigation("Type");
+                });
+
+            modelBuilder.Entity("TickAPI.Customers.Models.Customer", b =>
+                {
+                    b.Navigation("Tickets");
+                });
+
+            modelBuilder.Entity("TickAPI.Events.Models.Event", b =>
+                {
+                    b.Navigation("TicketTypes");
+                });
+
+            modelBuilder.Entity("TickAPI.Organizers.Models.Organizer", b =>
+                {
+                    b.Navigation("Events");
+                });
+
+            modelBuilder.Entity("TickAPI.TicketTypes.Models.TicketType", b =>
+                {
+                    b.Navigation("Tickets");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}
diff --git a/TickAPI/TickAPI/Migrations/20250401224843_NullableLastNames.cs b/TickAPI/TickAPI/Migrations/20250401224843_NullableLastNames.cs
new file mode 100644
index 0000000..e7741a4
--- /dev/null
+++ b/TickAPI/TickAPI/Migrations/20250401224843_NullableLastNames.cs
@@ -0,0 +1,54 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace TickAPI.Migrations
+{
+    /// <inheritdoc />
+    public partial class NullableLastNames : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AlterColumn<string>(
+                name: "LastName",
+                table: "Organizers",
+                type: "nvarchar(max)",
+                nullable: true,
+                oldClrType: typeof(string),
+                oldType: "nvarchar(max)");
+
+            migrationBuilder.AlterColumn<string>(
+                name: "LastName",
+                table: "Customers",
+                type: "nvarchar(max)",
+                nullable: true,
+                oldClrType: typeof(string),
+                oldType: "nvarchar(max)");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AlterColumn<string>(
+                name: "LastName",
+                table: "Organizers",
+                type: "nvarchar(max)",
+                nullable: false,
+                defaultValue: "",
+                oldClrType: typeof(string),
+                oldType: "nvarchar(max)",
+                oldNullable: true);
+
+            migrationBuilder.AlterColumn<string>(
+                name: "LastName",
+                table: "Customers",
+                type: "nvarchar(max)",
+                nullable: false,
+                defaultValue: "",
+                oldClrType: typeof(string),
+                oldType: "nvarchar(max)",
+                oldNullable: true);
+        }
+    }
+}
diff --git a/TickAPI/TickAPI/Migrations/TickApiDbContextModelSnapshot.cs b/TickAPI/TickAPI/Migrations/TickApiDbContextModelSnapshot.cs
index c622432..ca59a48 100644
--- a/TickAPI/TickAPI/Migrations/TickApiDbContextModelSnapshot.cs
+++ b/TickAPI/TickAPI/Migrations/TickApiDbContextModelSnapshot.cs
@@ -37,6 +37,38 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                     b.ToTable("CategoryEvent");
                 });
 
+            modelBuilder.Entity("TickAPI.Addresses.Models.Address", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<string>("City")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("Country")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<long?>("FlatNumber")
+                        .HasColumnType("bigint");
+
+                    b.Property<long?>("HouseNumber")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("PostalCode")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("Street")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Addresses");
+                });
+
             modelBuilder.Entity("TickAPI.Admins.Models.Admin", b =>
                 {
                     b.Property<Guid>("Id")
@@ -89,7 +121,6 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                         .HasColumnType("nvarchar(max)");
 
                     b.Property<string>("LastName")
-                        .IsRequired()
                         .HasColumnType("nvarchar(max)");
 
                     b.HasKey("Id");
@@ -97,38 +128,6 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                     b.ToTable("Customers");
                 });
 
-            modelBuilder.Entity("TickAPI.Events.Models.Address", b =>
-                {
-                    b.Property<Guid>("Id")
-                        .ValueGeneratedOnAdd()
-                        .HasColumnType("uniqueidentifier");
-
-                    b.Property<string>("City")
-                        .IsRequired()
-                        .HasColumnType("nvarchar(max)");
-
-                    b.Property<string>("Country")
-                        .IsRequired()
-                        .HasColumnType("nvarchar(max)");
-
-                    b.Property<long?>("FlatNumber")
-                        .HasColumnType("bigint");
-
-                    b.Property<long?>("HouseNumber")
-                        .HasColumnType("bigint");
-
-                    b.Property<string>("PostalCode")
-                        .IsRequired()
-                        .HasColumnType("nvarchar(max)");
-
-                    b.Property<string>("Street")
-                        .HasColumnType("nvarchar(max)");
-
-                    b.HasKey("Id");
-
-                    b.ToTable("Addresses");
-                });
-
             modelBuilder.Entity("TickAPI.Events.Models.Event", b =>
                 {
                     b.Property<Guid>("Id")
@@ -195,7 +194,6 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                         .HasColumnType("bit");
 
                     b.Property<string>("LastName")
-                        .IsRequired()
                         .HasColumnType("nvarchar(max)");
 
                     b.HasKey("Id");
@@ -284,7 +282,7 @@ protected override void BuildModel(ModelBuilder modelBuilder)
 
             modelBuilder.Entity("TickAPI.Events.Models.Event", b =>
                 {
-                    b.HasOne("TickAPI.Events.Models.Address", "Address")
+                    b.HasOne("TickAPI.Addresses.Models.Address", "Address")
                         .WithMany()
                         .HasForeignKey("AddressId")
                         .OnDelete(DeleteBehavior.Cascade)
diff --git a/TickAPI/TickAPI/Organizers/Models/Organizer.cs b/TickAPI/TickAPI/Organizers/Models/Organizer.cs
index b7ed81e..f55cc05 100644
--- a/TickAPI/TickAPI/Organizers/Models/Organizer.cs
+++ b/TickAPI/TickAPI/Organizers/Models/Organizer.cs
@@ -8,7 +8,7 @@ public class Organizer
     public Guid Id { get; set; }
     public string Email { get; set; }
     public string FirstName { get; set; }
-    public string LastName { get; set; }
+    public string? LastName { get; set; }
     public DateTime CreationDate { get; set; }
     public string DisplayName { get; set; }
     public bool IsVerified { get; set; }