diff --git a/Modules/zlibmodule.c b/Modules/zlibmodule.c
index 0a6732835eb51f..370ace8dc07203 100644
--- a/Modules/zlibmodule.c
+++ b/Modules/zlibmodule.c
@@ -2209,6 +2209,9 @@ zlib_exec(PyObject *mod)
     }
 
     state->ZlibError = PyErr_NewException("zlib.error", NULL, NULL);
+    if (state->ZlibError == NULL) {
+        return -1;
+    }
     if (PyModule_AddObjectRef(mod, "error", state->ZlibError) < 0) {
         return -1;
     }