diff --git a/lex.js b/lex.js
index 3b93d76..11a3e5a 100644
--- a/lex.js
+++ b/lex.js
@@ -10,7 +10,14 @@ module.exports.create = function (opts) {
   };
 
   opts.listen = function (plainPort, port) {
-    var PromiseA = require('bluebird');
+    var PromiseA;
+    try {
+      PromiseA = require('bluebird');
+    } catch(e) {
+      console.warn("Package 'bluebird' not installed. Using global.Promise instead");
+      console.warn("(want bluebird instead? npm install --save bluebird)");
+      PromiseA = global.Promise;
+    }
     var promises = [];
     var plainPorts = plainPort;
     var ports = port;