diff --git a/Parser/pgen.c b/Parser/pgen.c
index 76cb204751e..959a5d3443f 100644
--- a/Parser/pgen.c
+++ b/Parser/pgen.c
@@ -667,6 +667,7 @@ pgen(node *n)
 	g = maketables(gr);
 	translatelabels(g);
 	addfirstsets(g);
+	PyObject_FREE(gr);
 	return g;
 }