diff --git a/lib/timers.js b/lib/timers.js
index d6fede1fa04..86738047a72 100644
--- a/lib/timers.js
+++ b/lib/timers.js
@@ -148,6 +148,7 @@ exports.active = function(item) {
 exports.setTimeout = function(callback, after) {
   var timer;
 
+  after = Math.floor(after);
   if (after <= 0) {
     // Use the slow case for after == 0
     timer = new Timer();
@@ -201,7 +202,7 @@ exports.clearTimeout = function(timer) {
 
 exports.setInterval = function(callback, repeat) {
   var timer = new Timer();
-
+  repeat = Math.floor(repeat);
   if (arguments.length > 2) {
     var args = Array.prototype.slice.call(arguments, 2);
     timer.callback = function() {