diff --git a/ds.c b/ds.c
index 2550583..81f6084 100644
--- a/ds.c
+++ b/ds.c
@@ -153,7 +153,7 @@ ds_hmp_t
 }
 
 void
-ds_hmp_free(ds_hmp_t **hmp)
+ds_hmp_free(ds_hmp_t **hmp, void kv_callback(_ds_hmp_kv_t *kv))
 {
 	int i;
 	_ds_hmp_kv_t *kv;
@@ -167,6 +167,9 @@ ds_hmp_free(ds_hmp_t **hmp)
 		ll = (*hmp)->data[i];
 		while (ll && ll->data) {
 			if ((kv = ds_sll_remove(&ll, 0))) {
+				if (kv_callback) {
+					kv_callback(kv);
+				}
 				free(kv);
 			}
 		}
diff --git a/ds.h b/ds.h
index bf3c243..18a000f 100644
--- a/ds.h
+++ b/ds.h
@@ -89,7 +89,7 @@ ds_hmp_t *ds_hmp_init(int data_len);
  *
  * @param hmp pointer to the hashmap
  */
-void ds_hmp_free(ds_hmp_t **hmp);
+void ds_hmp_free(ds_hmp_t **hmp, void kv_callback(_ds_hmp_kv_t *kv));
 
 /**
  * @brief generate a numerical hash from a given string. You shouldn't need to