diff --git a/Gigya.ServiceContract/HttpService/ServiceSchema.cs b/Gigya.ServiceContract/HttpService/ServiceSchema.cs
index d033934f..0500eee7 100644
--- a/Gigya.ServiceContract/HttpService/ServiceSchema.cs
+++ b/Gigya.ServiceContract/HttpService/ServiceSchema.cs
@@ -52,6 +52,7 @@ public ServiceSchema(Type[] interfaces)
             SetHashCode();
         }
 
+        // TODO: Why?
         public string Hash { get; set; }
 
         private void SetHashCode()
@@ -192,10 +193,36 @@ public TypeSchema(Type type, IEnumerable<Attribute> attributes) : base(type, att
 
         private IEnumerable<FieldSchema> GetFields(Type type)
         {
-            var baseFields = type.BaseType != typeof(object) && type.BaseType != null ? GetFields(type.BaseType) : new FieldSchema[0];
-            var properties = type.GetProperties().Select(_ => new FieldSchema(_));
-            var fields = type.GetFields().Select(_ => new FieldSchema(_));
-            return baseFields.Concat(properties).Concat(fields);
+            var fields = new Dictionary<string, FieldSchema>();
+            
+            while (type != null)
+            {
+                void add(FieldSchema fs)
+                {
+                    if (fields.TryGetValue(fs.Name, out var s))
+                        s.Attributes = s.Attributes.Union(fs.Attributes).ToArray();
+                    else
+                        fields.Add(fs.Name, fs);
+                }
+
+                void addRange(IEnumerable<FieldSchema> fss)
+                {
+                    foreach (var fs in fss)
+                        add(fs);
+                }
+
+                addRange(type
+                    .GetFields(BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly)
+                    .Select(x => new FieldSchema(x)));
+
+                addRange(type
+                    .GetProperties(BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly)
+                    .Select(x => new FieldSchema(x)));
+                
+                type = type.BaseType;
+            }
+
+            return fields.Values;
         }
 
         private bool IsCompositeType(Type type)
diff --git a/tests/Gigya.Microdot.ServiceContract.UnitTests/ServiceSchemaTests.cs b/tests/Gigya.Microdot.ServiceContract.UnitTests/ServiceSchemaTests.cs
index 2b0c5fc5..3ed329bf 100644
--- a/tests/Gigya.Microdot.ServiceContract.UnitTests/ServiceSchemaTests.cs
+++ b/tests/Gigya.Microdot.ServiceContract.UnitTests/ServiceSchemaTests.cs
@@ -33,11 +33,15 @@ class DataParamBase
     {
         [Sensitive]
         public int BaseField;
+
+        public virtual int VirtProp { get; set; }
     }
     class Data: DataParamBase
     {
         public string s;
         public Nested n;
+
+        public override int VirtProp { get => base.VirtProp; set => base.VirtProp = value; }
     }
 
     class Nested
@@ -60,6 +64,35 @@ internal interface ITestInterface
         Task<ResponseData> DoSomething(int i, double? nd, string s, [Sensitive] Data data);
     }
 
+    abstract class AbctractClass
+    {
+        public abstract int PropAbstractVirtual { get; set; }
+        public abstract int PropAbstract { get; set; }
+    }
+
+    class VirtClass : AbctractClass
+    {
+        public int fldHidden;
+        public override int PropAbstractVirtual { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
+        public override int PropAbstract { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
+
+        public virtual int PropVirtual { get; set; }
+    }
+
+    class SpecificClass : VirtClass
+    {
+        // TODO: UB
+        public new int fldHidden;
+        public override int PropAbstractVirtual { get => base.PropAbstractVirtual; set => base.PropAbstractVirtual = value; }
+        public override int PropVirtual { get => base.PropVirtual; set => base.PropVirtual = value; }
+    }
+
+    internal interface IDoublesTest
+    {
+        [PublicEndpoint("test")]
+        Task Test(SpecificClass obj);
+    }
+
     [TestFixture,Parallelizable(ParallelScope.Fixtures)]
     public class ServiceSchemaTests
     {
@@ -93,11 +126,11 @@ public void TestSerialization()
             Assert.IsTrue(schema.Interfaces[0].Methods[0].Parameters[2].Name == "s");
             Assert.IsTrue(schema.Interfaces[0].Methods[0].Parameters[3].Attributes.Length == 1);
             Assert.IsTrue(schema.Interfaces[0].Methods[0].Parameters[3].Attributes[0].Attribute is SensitiveAttribute);
-            Assert.IsTrue(schema.Interfaces[0].Methods[0].Parameters[3].Fields[0].Name == nameof(DataParamBase.BaseField));
-            Assert.IsTrue(schema.Interfaces[0].Methods[0].Parameters[3].Fields[0].Attributes[0].Attribute is SensitiveAttribute);
-            Assert.IsTrue(schema.Interfaces[0].Methods[0].Parameters[3].Fields[0].Type == typeof(int));
-            Assert.IsTrue(schema.Interfaces[0].Methods[0].Parameters[3].Fields[1].Name == nameof(Data.s));
-            Assert.IsTrue(schema.Interfaces[0].Methods[0].Parameters[3].Fields[1].Type == typeof(string));
+            Assert.IsTrue(schema.Interfaces[0].Methods[0].Parameters[3].Fields[3].Name == nameof(DataParamBase.BaseField));
+            Assert.IsTrue(schema.Interfaces[0].Methods[0].Parameters[3].Fields[3].Attributes[0].Attribute is SensitiveAttribute);
+            Assert.IsTrue(schema.Interfaces[0].Methods[0].Parameters[3].Fields[3].Type == typeof(int));
+            Assert.IsTrue(schema.Interfaces[0].Methods[0].Parameters[3].Fields[0].Name == nameof(Data.s));
+            Assert.IsTrue(schema.Interfaces[0].Methods[0].Parameters[3].Fields[0].Type == typeof(string));
             Assert.IsTrue(schema.Interfaces[0].Methods[0].Response.Type == typeof(ResponseData));
             Assert.IsTrue(schema.Interfaces[0].Methods[0].Response.Fields[0].Name == nameof(ResponseData.a));
             Assert.IsTrue(schema.Interfaces[0].Methods[0].Response.Fields[0].Type == typeof(string));
@@ -105,6 +138,14 @@ public void TestSerialization()
             Assert.IsTrue(schema.Interfaces[0].Methods[0].Response.Fields[1].Type == typeof(int));
         }
 
+        [Test]
+        public void ServiceSchema_DoesntContainDuplicates()
+        {
+            ServiceSchema schema = new ServiceSchema(new[] { typeof(IDoublesTest) });
+
+            Assert.AreEqual(4, schema.Interfaces[0].Methods[0].Parameters[0].Fields.Length);
+        }
+
 
         [Test]
         public void TestUnknownAttribute()