diff --git a/dist/async.min.js b/dist/async.min.js
index 53d445921..dfa2988e1 100644
--- a/dist/async.min.js
+++ b/dist/async.min.js
@@ -1 +1 @@
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\ No newline at end of file
+/*global setTimeout: false, console: false */(function(){var a={};var b=this,c=b.async;typeof module!=="undefined"&&module.exports?module.exports=a:b.async=a,a.noConflict=function(){b.async=c;return a};var d=function(a,b){if(a.forEach)return a.forEach(b);for(var c=0;c<a.length;c+=1)b(a[c],c,a)};var e=function(a,b){if(a.map)return a.map(b);var c=[];d(a,function(a,d,e){c.push(b(a,d,e))});return c};var f=function(a,b,c){if(a.reduce)return a.reduce(b,c);d(a,function(a,d,e){c=b(c,a,d,e)});return c};var g=function(a){if(Object.keys)return Object.keys(a);var b=[];for(var c in a)a.hasOwnProperty(c)&&b.push(c);return b};var h=function(a,b){if(a.indexOf)return a.indexOf(b);for(var c=0;c<a.length;c+=1)if(a[c]===b)return c;return-1};a.nextTick=function(a){typeof process==="undefined"||!process.nextTick?setTimeout(a,0):process.nextTick(a)},a.forEach=function(a,b,c){if(!a.length)return c();var 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\ No newline at end of file
diff --git a/lib/async.js b/lib/async.js
index 62f2e43e6..c8fccc3ef 100644
--- a/lib/async.js
+++ b/lib/async.js
@@ -559,7 +559,9 @@
                     workers += 1;
                     worker(task.data, function () {
                         workers -= 1;
-                        task.callback.apply(task, arguments);
+                        if (task.callback) {
+                            task.callback.apply(task, arguments);
+                        }
                         q.process();
                     });
                 }
diff --git a/test/test-async.js b/test/test-async.js
index 1c694b569..73c42cf2b 100644
--- a/test/test-async.js
+++ b/test/test-async.js
@@ -1160,3 +1160,34 @@ exports['queue changing concurrency'] = function (test) {
         test.done();
     }, 100);
 };
+
+exports['queue push without callback'] = function (test) {
+    var call_order = [],
+        delays = [20,10,30,10];
+
+    // worker1: --1-4
+    // worker2: -2---3
+    // order of completion: 2,1,4,3
+
+    var q = async.queue(function (task, callback) {
+        setTimeout(function () {
+            call_order.push('process ' + task);
+            callback('error', 'arg');
+        }, delays.splice(0,1)[0]);
+    }, 2);
+
+    q.push(1);
+    q.push(2);
+    q.push(3);
+    q.push(4);
+
+    setTimeout(function () {
+        test.same(call_order, [
+            'process 2',
+            'process 1',
+            'process 4',
+            'process 3'
+        ]);
+        test.done();
+    }, 60);
+};