diff --git a/src/ep_util.c b/src/ep_util.c
index f4a1c3a..44a49c8 100644
--- a/src/ep_util.c
+++ b/src/ep_util.c
@@ -62,7 +62,7 @@ HRESULT Epython_register_constants(PyObject *module, PCREGCONSTANT const_table)
 	    Log(LERROR, "register_constants type '%c' unknown", const_table[i].regtype);
 	    return E_UNEXPECTED;
 	}
-	if (!rc)
+	if (rc)
 	{
 	  Log(LERROR, "Failed to register constant %s", const_table[i].name);
 	  hr = E_FAIL;