diff --git a/mysql-test/r/func_misc.result b/mysql-test/r/func_misc.result
index f0262acd71e..6b6277ea649 100644
--- a/mysql-test/r/func_misc.result
+++ b/mysql-test/r/func_misc.result
@@ -134,4 +134,11 @@ timediff(b, a) >= '00:00:03'
 drop table t2;
 drop table t1;
 set global query_cache_size=default;
+create table t1 select INET_ATON('255.255.0.1') as `a`;
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `a` bigint(21) unsigned default NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+drop table t1;
 End of 5.0 tests
diff --git a/mysql-test/t/func_misc.test b/mysql-test/t/func_misc.test
index 52a5512d070..5cac6c45f65 100644
--- a/mysql-test/t/func_misc.test
+++ b/mysql-test/t/func_misc.test
@@ -125,4 +125,11 @@ drop table t2;
 drop table t1;
 set global query_cache_size=default;
 
+#
+# Bug #21466: INET_ATON() returns signed, not unsigned
+#
+
+create table t1 select INET_ATON('255.255.0.1') as `a`;
+show create table t1;
+drop table t1;
 --echo End of 5.0 tests
diff --git a/sql/item_func.h b/sql/item_func.h
index 177daf0311f..0a821733a29 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -1289,7 +1289,7 @@ public:
    Item_func_inet_aton(Item *a) :Item_int_func(a) {}
    longlong val_int();
    const char *func_name() const { return "inet_aton"; }
-   void fix_length_and_dec() { decimals = 0; max_length = 21; maybe_null=1;}
+   void fix_length_and_dec() { decimals = 0; max_length = 21; maybe_null=1;unsigned_flag=1;}
 };