diff --git a/Modules/ossaudiodev.c b/Modules/ossaudiodev.c
index 7686902..6654d71 100644
--- a/Modules/ossaudiodev.c
+++ b/Modules/ossaudiodev.c
@@ -986,11 +986,17 @@
 	NULL
 };
 
-PyObject*
+PyMODINIT_FUNC
 PyInit_ossaudiodev(void)
 {
     PyObject *m;
 
+    if (PyType_Ready(&OSSAudioType) < 0)
+        return NULL;
+
+    if (PyType_Ready(&OSSMixerType) < 0)
+        return NULL;
+
     m = PyModule_Create(&ossaudiodevmodule);
     if (m == NULL)
 	return NULL;