diff --git a/idl_parser/module.py b/idl_parser/module.py
index 482dd91..ab3a41b 100644
--- a/idl_parser/module.py
+++ b/idl_parser/module.py
@@ -91,8 +91,13 @@ def parse_tokens(self, token_buf, filepath=None):
                     else:
                         blocks.append(t)
                 t = typedef.IDLTypedef(self)
-                self._typedefs.append(t)
                 t.parse_blocks(blocks, filepath=filepath)
+                t_ = self.typedef_by_name(t.name)
+                if t_:
+                    if self._verbose: sys.stdout.write('# Error. Same Typedef Defined (%s)\n' % t.name)
+                else:
+                    self._typedefs.append(t)
+
             elif token == 'struct':
                 ln, fn, name_ = token_buf.pop()
                 s_ = self.struct_by_name(name_)