@@ -318,6 +318,17 @@ internal static bool ToManagedValue(IntPtr value, Type obType,
                 return true;
             }
 
+            if (obType.IsGenericType && obType.GetGenericTypeDefinition() == typeof(Nullable<>))
+            {
+                if( value == Runtime.PyNone )
+                {
+                    result = null;
+                    return true;
+                }
+                // Set type to underlying type
+                obType = obType.GetGenericArguments()[0];
+            }
+
             if (obType.IsArray)
             {
                 return ToArray(value, obType, out result, setError);
 
@@ -32,8 +32,14 @@ public ConversionTest()
 
         public byte[] ByteArrayField;
         public sbyte[] SByteArrayField;
+
+        public T? Echo<T>(T? arg) where T: struct {
+            return arg;
+        }
+
     }
 
+    
 
     public interface ISpam
     {
 
@@ -641,6 +641,8 @@ def test_enum_conversion():
 
 def test_null_conversion():
     """Test null conversion."""
+    import System
+    
     ob = ConversionTest()
 
     ob.StringField = None
@@ -652,6 +654,10 @@ def test_null_conversion():
     ob.SpamField = None
     assert ob.SpamField is None
 
+    pi = 22/7
+    assert ob.Echo[System.Double](pi) == pi
+    assert ob.Echo[System.DateTime](None) is None
+
     # Primitive types and enums should not be set to null.
 
     with pytest.raises(TypeError):
Original file line number	Diff line number	Diff line change
@@ -32,8 +32,14 @@ public ConversionTest()
32	32
33	33	public byte[] ByteArrayField;
34	34	public sbyte[] SByteArrayField;
	35	+
	36	+ public T? Echo<T>(T? arg) where T: struct {
	37	+ return arg;
	38	+ }
	39	+
35	40	}
36	41
	42	+
37	43
38	44	public interface ISpam
39	45	{