diff --git a/lib/spdylay_map.c b/lib/spdylay_map.c
index 0451f582..0ada828d 100644
--- a/lib/spdylay_map.c
+++ b/lib/spdylay_map.c
@@ -164,12 +164,14 @@ static spdylay_map_entry* erase_rotate_recur(spdylay_map_entry *entry)
 
 static spdylay_map_entry* erase_recur(spdylay_map_entry *entry, key_type key)
 {
-  if(key < entry->key) {
-    entry->left = erase_recur(entry->left, key);
-  } else if(key > entry->key) {
-    entry->right = erase_recur(entry->right, key);
-  } else {
-    entry = erase_rotate_recur(entry);
+  if(entry != NULL) {
+    if(key < entry->key) {
+      entry->left = erase_recur(entry->left, key);
+    } else if(key > entry->key) {
+      entry->right = erase_recur(entry->right, key);
+    } else {
+      entry = erase_rotate_recur(entry);
+    }
   }
   return entry;
 }
diff --git a/tests/spdylay_map_test.c b/tests/spdylay_map_test.c
index 49481133..0c67c90f 100644
--- a/tests/spdylay_map_test.c
+++ b/tests/spdylay_map_test.c
@@ -47,9 +47,11 @@ void test_spdylay_map()
   spdylay_map_erase(&map, 1);
   CU_ASSERT(NULL == spdylay_map_find(&map, 1));
 
+  spdylay_map_erase(&map, 1);
+  CU_ASSERT(NULL == spdylay_map_find(&map, 1));
+
   CU_ASSERT(strcmp("bar", spdylay_map_find(&map, 2)) == 0);
   CU_ASSERT(strcmp("shrubbery", spdylay_map_find(&map, 4)) == 0);
 
   spdylay_map_free(&map);
 }
-