diff --git a/src/Base/PyObjectBase.h b/src/Base/PyObjectBase.h
index 76b0e72fcd..c916703c93 100644
--- a/src/Base/PyObjectBase.h
+++ b/src/Base/PyObjectBase.h
@@ -52,9 +52,7 @@
 #include <cstring>
 
 #include "Exception.h"
-#ifndef PYCXX_PYTHON_2TO3
-#define PYCXX_PYTHON_2TO3
-#endif
+
 #include <CXX/Objects.hxx>