diff --git a/src/raven.js b/src/raven.js
index a2d2b35604b4..fb9d2a15499a 100644
--- a/src/raven.js
+++ b/src/raven.js
@@ -805,13 +805,37 @@ function joinRegExp(patterns) {
     return new RegExp(sources.join('|'), 'i');
 }
 
-// http://stackoverflow.com/questions/105034/how-to-create-a-guid-uuid-in-javascript/2117523#2117523
 function uuid4() {
-    return 'xxxxxxxxxxxx4xxxyxxxxxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
-        var r = Math.random()*16|0,
-            v = c == 'x' ? r : (r&0x3|0x8);
-        return v.toString(16);
-    });
+    var crypto = window.crypto || window.msCrypto;
+
+    if (!isUndefined(crypto) && crypto.getRandomValues) {
+        // Use window.crypto API if available
+        var arr = new Uint16Array(8);
+        crypto.getRandomValues(arr);
+
+        // set 4 in byte 7
+        arr[3] = arr[3] & 0xFFF | 0x4000;
+        // set 2 most significant bits of byte 9 to '10'
+        arr[4] = arr[4] & 0x3FFF | 0x8000;
+
+        var pad = function(num) {
+            var v = num.toString(16);
+            while (v.length < 4) {
+                v = '0' + v;
+            }
+            return v;
+        };
+
+        return (pad(arr[0]) + pad(arr[1]) + pad(arr[2]) + pad(arr[3]) + pad(arr[4]) +
+        pad(arr[5]) + pad(arr[6]) + pad(arr[7]));
+    } else {
+        // http://stackoverflow.com/questions/105034/how-to-create-a-guid-uuid-in-javascript/2117523#2117523
+        return 'xxxxxxxxxxxx4xxxyxxxxxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
+            var r = Math.random()*16|0,
+                v = c == 'x' ? r : (r&0x3|0x8);
+            return v.toString(16);
+        });
+    }
 }
 
 function logDebug(level, message) {