diff --git a/lib/LRUCacheProxy.js b/lib/LRUCacheProxy.js
index 26680ce..a8e7dc2 100644
--- a/lib/LRUCacheProxy.js
+++ b/lib/LRUCacheProxy.js
@@ -28,7 +28,7 @@ var LRUCacheProxy = function LRUCacheProxy(options) {
 			var lruGet = LRUCache.prototype.get;
 
 			lru.get = function(key, callback) {
-				callback(lruGet.apply(lru, arguments));
+				callback && callback(lruGet.apply(lru, arguments));
 			};
 
 			return lru;