diff --git a/ctypes_generation/definitions/flag.py b/ctypes_generation/definitions/flag.py
index 2d5158f..8982d11 100644
--- a/ctypes_generation/definitions/flag.py
+++ b/ctypes_generation/definitions/flag.py
@@ -12,7 +12,7 @@ class Flag(long):
         self.name = name
 
     def __repr__(self):
-        return "{0}({1})".format(self.name, hex(self))
+        return "{0}({1:#x})".format(self.name, self)
 
     __str__ = __repr__