diff --git a/c_src/mqtree.c b/c_src/mqtree.c
index 56724e0..a90c340 100644
--- a/c_src/mqtree.c
+++ b/c_src/mqtree.c
@@ -205,7 +205,7 @@ int register_tree(char *name, state_t *state) {
 
   entry->name = enif_alloc(strlen(name) + 1);
   if (!entry->name) {
-    free(entry);
+    enif_free(entry);
     return ENOMEM;
   }