diff --git a/lib/table.js b/lib/table.js
index 66a96fb..4aa646f 100644
--- a/lib/table.js
+++ b/lib/table.js
@@ -256,7 +256,13 @@ Table.prototype.update = function (item, options, callback) {
     if(err) {
       return callback(err);
     }
+    
+    var result = self.schema.validate(data);
 
+    if(result.error) {
+      return callback(result.error);
+    }
+    
     var hashKey = data[self.schema.hashKey];
     var rangeKey = data[self.schema.rangeKey] || null;