diff --git a/lib/config.js b/lib/config.js
index <HASH>..<HASH> 100644
--- a/lib/config.js
+++ b/lib/config.js
@@ -88,6 +88,11 @@ function configureHandler(handler, options) {
 
 function getHandler(name, options) {
   var handler = options.handlers[name];
+  if (!handler) {
+    var errorStr = util.format('Handler "%s" is undefined.' +
+      ' Probably you shoud check your config', name);
+    throw new Error(errorStr);
+  }
   if (typeof handler.handle !== 'function') {
     handler = options.handlers[name] = configureHandler(handler, options);
   }
Throw error if handler is not defined in config