diff --git a/src/runtime/converter.cs b/src/runtime/converter.cs
@@ -698,19 +698,10 @@ private static bool ToPrimitive(IntPtr value, Type obType, out object result, bo

                case TypeCode.UInt64:
                    {
-                        op = value;
-                        if (Runtime.PyObject_TYPE(value) != Runtime.PyLongType)
-                        {
-                            op = Runtime.PyNumber_Long(value);
-                            if (op == IntPtr.Zero)
-                            {
-                                goto convert_error;
-                            }
-                        }
-                        ulong num = Runtime.PyLong_AsUnsignedLongLong(op);
                        if (num == ulong.MaxValue && Exceptions.ErrorOccurred())
                        {
-                            goto overflow;
                        }
                        result = num;
                        return true;

diff --git a/src/tests/test_conversion.py b/src/tests/test_conversion.py
@@ -382,7 +382,10 @@ def test_uint64_conversion():
    ob.UInt64Field = System.UInt64(0)
    assert ob.UInt64Field == 0

-    with pytest.raises(ValueError):
        ConversionTest().UInt64Field = "spam"

    with pytest.raises(TypeError):