diff --git a/mysql-test/r/federated.result b/mysql-test/r/federated.result
index 5d17afd8cfc..5e827a34e87 100644
--- a/mysql-test/r/federated.result
+++ b/mysql-test/r/federated.result
@@ -1784,6 +1784,33 @@ length(a)
 5000
 drop table t1;
 drop table t1;
+DROP TABLE IF EXISTS federated.test;
+CREATE TABLE federated.test (
+`i` int(11) NOT NULL,
+`j` int(11) NOT NULL,
+`c` varchar(30) default NULL,
+PRIMARY KEY  (`i`,`j`),
+UNIQUE KEY `i` (`i`,`c`)
+) ENGINE=InnoDB DEFAULT CHARSET=latin1;
+DROP TABLE IF EXISTS federated.test1;
+DROP TABLE IF EXISTS federated.test2;
+create table federated.test1 (
+i int not null,
+j int not null,
+c varchar(30),
+primary key (i,j),
+unique key (i, c))
+engine = federated
+connection='mysql://root@127.0.0.1:SLAVE_PORT/federated/test';
+create table federated.test2 (
+i int default null,
+j int not null,
+c varchar(30),
+key (i))
+engine = federated
+connection='mysql://root@127.0.0.1:SLAVE_PORT/federated/test';
+drop table federated.test1, federated.test2;
+drop table federated.test;
 DROP TABLE IF EXISTS federated.t1;
 DROP DATABASE IF EXISTS federated;
 DROP TABLE IF EXISTS federated.t1;
diff --git a/mysql-test/t/federated.test b/mysql-test/t/federated.test
index 38beab605fd..c2218b3451b 100644
--- a/mysql-test/t/federated.test
+++ b/mysql-test/t/federated.test
@@ -1499,4 +1499,49 @@ drop table t1;
 connection master;
 drop table t1;
 
+#
+# BUG #15133: unique index with nullable value not accepted in federated table 
+#
+
+connection slave;
+--disable_warnings
+DROP TABLE IF EXISTS federated.test;
+CREATE TABLE federated.test (
+  `i` int(11) NOT NULL,
+  `j` int(11) NOT NULL,
+  `c` varchar(30) default NULL,
+  PRIMARY KEY  (`i`,`j`),
+  UNIQUE KEY `i` (`i`,`c`)
+) ENGINE=InnoDB DEFAULT CHARSET=latin1;
+--enable_warnings
+
+connection master;
+--disable_warnings
+DROP TABLE IF EXISTS federated.test1;
+DROP TABLE IF EXISTS federated.test2;
+--enable_warnings
+
+--replace_result $SLAVE_MYPORT SLAVE_PORT
+eval create table federated.test1 (
+        i int not null,
+        j int not null,
+        c varchar(30),
+        primary key (i,j),
+        unique key (i, c))
+engine = federated
+connection='mysql://root@127.0.0.1:$SLAVE_MYPORT/federated/test';
+
+--replace_result $SLAVE_MYPORT SLAVE_PORT
+eval create table federated.test2 (
+        i int default null,
+        j int not null,
+        c varchar(30),
+        key (i))
+engine = federated
+connection='mysql://root@127.0.0.1:$SLAVE_MYPORT/federated/test';
+drop table federated.test1, federated.test2;
+
+connection slave;
+drop table federated.test;
+
 source include/federated_cleanup.inc;
diff --git a/sql/ha_federated.h b/sql/ha_federated.h
index 85474d142a3..61f5af686a3 100644
--- a/sql/ha_federated.h
+++ b/sql/ha_federated.h
@@ -196,7 +196,9 @@ public:
     /* fix server to be able to get remote server table flags */
     return (HA_NOT_EXACT_COUNT |
             HA_PRIMARY_KEY_IN_READ_INDEX | HA_FILE_BASED | HA_REC_NOT_IN_SEQ |
-            HA_AUTO_PART_KEY | HA_CAN_INDEX_BLOBS| HA_NO_PREFIX_CHAR_KEYS);
+            HA_AUTO_PART_KEY | HA_CAN_INDEX_BLOBS| HA_NO_PREFIX_CHAR_KEYS |
+	    HA_NULL_IN_KEY
+	);
   }
   /*
     This is a bitmap of flags that says how the storage engine