diff --git a/mpc.c b/mpc.c
index eab30f4..b90f0be 100644
--- a/mpc.c
+++ b/mpc.c
@@ -2542,6 +2542,7 @@ mpc_ast_t *mpc_ast_new(const char *tag, const char *contents) {
   
   a->children_num = 0;
   a->children = NULL;
+  a->data = NULL;
   return a;
   
 }