diff --git a/memcache.inc b/memcache.inc
index da2f8be..9362c29 100644
--- a/memcache.inc
+++ b/memcache.inc
@@ -151,6 +151,11 @@ class MemCacheDrupal implements DrupalCacheInterface {
       $memcache_expire = $cache->expire + (($cache->expire - REQUEST_TIME) * 2);
     }
     dmemcache_set($cid, $cache, $memcache_expire, $this->bin, $this->memcache);
+
+    // Try releasing the lock acquired in $this->valid().
+    if (variable_get('memcache_stampede_protection', FALSE)) {
+      lock_release("memcache_$cid:$this->bin");
+    }
   }
 
   function clear($cid = NULL, $wildcard = FALSE) {