diff --git a/lib/timers.js b/lib/timers.js
index d79f64a8be..06229ed97f 100644
--- a/lib/timers.js
+++ b/lib/timers.js
@@ -3,7 +3,7 @@ var L = require('_linklist');
 var assert = require('assert').ok;
 
 var debug;
-if (process.env.NODE_debug && /timer/.test(process.env.NODE_debug)) {
+if (process.env.NODE_DEBUG && /timer/.test(process.env.NODE_DEBUG)) {
   debug = function() { require('util').error.apply(this, arguments); };
 } else {
   debug = function() { };