diff --git a/lib/timers.js b/lib/timers.js
index 0dc9ed80b7e577..50ae477d59d30f 100644
--- a/lib/timers.js
+++ b/lib/timers.js
@@ -30,7 +30,7 @@ var lists = {};
 // with them.
 exports.active = function(item) {
   const msecs = item._idleTimeout;
-  if (msecs < 0) return;
+  if (msecs < 0 || msecs === undefined) return;
 
   item._idleStart = Timer.now();
 
diff --git a/test/parallel/test-timers-active.js b/test/parallel/test-timers-active.js
index 9162406848d195..acddc2f41a45e8 100644
--- a/test/parallel/test-timers-active.js
+++ b/test/parallel/test-timers-active.js
@@ -22,7 +22,8 @@ legitTimers.forEach(function(legit) {
 
 // active() should not create a timer for these
 var bogusTimers = [
-  { _idleTimeout: -1 }
+  { _idleTimeout: -1 },
+  { _idleTimeout: undefined },
 ];
 
 bogusTimers.forEach(function(bogus) {