diff --git a/psycopg/python.h b/psycopg/python.h
index 9567c965..f4256d8d 100644
--- a/psycopg/python.h
+++ b/psycopg/python.h
@@ -54,7 +54,7 @@
 #endif
 
 #ifndef Py_TYPE
-  #define Py_TYPE(o) ((o)->ob_type)
+  #define Py_TYPE(o) (((PyObject*)(o))->ob_type)
 #endif
 
 /* FORMAT_CODE_PY_SSIZE_T is for Py_ssize_t: */