diff --git a/browser/base/content/browser-fullScreen.js b/browser/base/content/browser-fullScreen.js
index 6b5a70f89b8..90c376245d6 100644
--- a/browser/base/content/browser-fullScreen.js
+++ b/browser/base/content/browser-fullScreen.js
@@ -96,7 +96,7 @@ var FullScreen = {
       TabsInTitlebar.updateAppearance(true);
     }
 
-    if (enterFS) {
+    if (enterFS && !document.mozFullScreen) {
       Services.telemetry.getHistogramById("FX_BROWSER_FULLSCREEN_USED")
                         .add(1);
     }