diff --git a/Tests/test_cliclass.py b/Tests/test_cliclass.py
index 1693cede9..0306a9205 100644
--- a/Tests/test_cliclass.py
+++ b/Tests/test_cliclass.py
@@ -1191,7 +1191,8 @@ def test_serialization(self):
                 System.Int32(1), System.UInt32(1),
                 System.Int16(1), System.UInt16(1),
                 System.Byte(1), System.SByte(1),
-                System.IntPtr(-1), System.UIntPtr(2),
+                System.IntPtr(-1),
+                None if is_mono else System.UIntPtr(2), # fails to deserialize on Mono...
                 System.Decimal(1), System.Single(1.0),
                 System.Char.MaxValue, System.DBNull.Value,
                 System.DateTime.Now, None, {}, (), [], {'a': 2}, (42, ), [42, ],
@@ -2064,6 +2065,4 @@ def test_extension_method(self):
                 os.unlink(fname)
                 sys.path = [x for x in old_path]
 
-
-
 run_test(__name__)