diff --git a/Parser/pgenmain.c b/Parser/pgenmain.c
index 52b8380c33f..a624dd2c61a 100644
--- a/Parser/pgenmain.c
+++ b/Parser/pgenmain.c
@@ -113,6 +113,7 @@ getgrammar(char *filename)
         Py_Exit(1);
     }
     g = pgen(n);
+    PyNode_Free(n);
     if (g == NULL) {
         printf("Bad grammar.\n");
         Py_Exit(1);