diff --git a/src/CacheElement.php b/src/CacheElement.php
index 9d4fbcf..777f07f 100644
--- a/src/CacheElement.php
+++ b/src/CacheElement.php
@@ -108,7 +108,7 @@ public function removeFromFs()
      */
     public function isAlive()
     {
-        return (time() - $this->_start) <= $this->_lifetime;
+        return $this->_lifetime == -1 || (time() - $this->_start) <= $this->_lifetime;
     }
 
     /**