diff --git a/mysql-test/r/func_concat.result b/mysql-test/r/func_concat.result
index cf6fbf2da4f..94f1f640523 100644
--- a/mysql-test/r/func_concat.result
+++ b/mysql-test/r/func_concat.result
@@ -64,3 +64,10 @@ select 'a' union select concat('a', -0.0);
 a
 a
 good
+select concat((select x from (select 'a' as x) as t1 ),
+(select y from (select 'b' as y) as t2 )) from (select 1 union select 2 )
+as t3;
+concat((select x from (select 'a' as x) as t1 ),
+(select y from (select 'b' as y) as t2 ))
+ab
+ab
diff --git a/mysql-test/t/func_concat.test b/mysql-test/t/func_concat.test
index 69ce10c83c9..f546a25f647 100644
--- a/mysql-test/t/func_concat.test
+++ b/mysql-test/t/func_concat.test
@@ -50,4 +50,11 @@ select 'a' union select concat('a', -0);
 --replace_result 'a-0.0' good 'a0.0' good
 select 'a' union select concat('a', -0.0);
 
+#
+# Bug#16716: subselect in concat() may lead to a wrong result
+#
+select concat((select x from (select 'a' as x) as t1 ),
+  (select y from (select 'b' as y) as t2 )) from (select 1 union select 2 )
+  as t3;
+
 # End of 4.1 tests
diff --git a/sql/item_strfunc.cc b/sql/item_strfunc.cc
index e74d0100b55..0dfbf3b7a1d 100644
--- a/sql/item_strfunc.cc
+++ b/sql/item_strfunc.cc
@@ -252,11 +252,13 @@ String *Item_func_concat::val_str(String *str)
   DBUG_ASSERT(fixed == 1);
   String *res,*res2,*use_as_buff;
   uint i;
+  bool is_const= 0;
 
   null_value=0;
   if (!(res=args[0]->val_str(str)))
     goto null;
   use_as_buff= &tmp_value;
+  is_const= args[0]->const_item();
   for (i=1 ; i < arg_count ; i++)
   {
     if (res->length() == 0)
@@ -279,7 +281,7 @@ String *Item_func_concat::val_str(String *str)
 			    current_thd->variables.max_allowed_packet);
 	goto null;
       }
-      if (res->alloced_length() >= res->length()+res2->length())
+      if (!is_const && res->alloced_length() >= res->length()+res2->length())
       {						// Use old buffer
 	res->append(*res2);
       }
@@ -334,6 +336,7 @@ String *Item_func_concat::val_str(String *str)
 	res= &tmp_value;
 	use_as_buff=str;
       }
+      is_const= 0;
     }
   }
   res->set_charset(collation.collation);