diff --git a/mysql-test/r/innodb.result b/mysql-test/r/innodb.result
index 2bdec5125dd..e0b477ab543 100644
--- a/mysql-test/r/innodb.result
+++ b/mysql-test/r/innodb.result
@@ -2475,3 +2475,11 @@ SELECT GRADE  FROM t1 WHERE GRADE= 151;
 GRADE
 151
 DROP TABLE t1;
+create table t1 (f1 varchar(10), f2 varchar(10), primary key (f1,f2)) engine=innodb;
+create table t2 (f3 varchar(10), f4 varchar(10), key (f4)) engine=innodb;
+insert into t2 values ('aa','cc');
+insert into t1 values ('aa','bb'),('aa','cc');
+delete t1 from t1,t2 where f1=f3 and f4='cc';
+select * from t1;
+f1	f2
+drop table t1,t2;
diff --git a/mysql-test/t/innodb.test b/mysql-test/t/innodb.test
index 05f47f36e42..0ec7faa8ade 100644
--- a/mysql-test/t/innodb.test
+++ b/mysql-test/t/innodb.test
@@ -1394,3 +1394,13 @@ SELECT GRADE  FROM t1 WHERE GRADE > 160 AND GRADE < 300;
 SELECT GRADE  FROM t1 WHERE GRADE= 151;
 DROP TABLE t1;
 
+#
+# Bug #12340 multitable delete deletes only one record
+#
+create table t1 (f1 varchar(10), f2 varchar(10), primary key (f1,f2)) engine=innodb;
+create table t2 (f3 varchar(10), f4 varchar(10), key (f4)) engine=innodb;
+insert into t2 values ('aa','cc');
+insert into t1 values ('aa','bb'),('aa','cc');
+delete t1 from t1,t2 where f1=f3 and f4='cc';
+select * from t1;
+drop table t1,t2;
diff --git a/sql/ha_innodb.cc b/sql/ha_innodb.cc
index d98222975c5..026bc0da13d 100644
--- a/sql/ha_innodb.cc
+++ b/sql/ha_innodb.cc
@@ -6852,8 +6852,8 @@ ha_innobase::cmp_ref(
 			return(result);
 		}
 
-		ref1 += key_part->length;
-		ref2 += key_part->length;
+		ref1 += key_part->store_length;
+		ref2 += key_part->store_length;
 	}
 
 	return(0);