--- a/toolkit/components/telemetry/TelemetryPing.js
+++ b/toolkit/components/telemetry/TelemetryPing.js
@@ -350,16 +350,20 @@ TelemetryPing.prototype = {
 
     let theme = LightweightThemeManager.currentTheme;
     if (theme)
       ret.persona = theme.id;
 
     if (this._addons)
       ret.addons = this._addons;
 
+    let flashVersion = this.getFlashVersion();
+    if (flashVersion)
+      ret.flashVersion = flashVersion;
+
     return ret;
   },
 
   /**
    * Pull values from about:memory into corresponding histograms
    */
   gatherMemory: function gatherMemory() {
     let mgr;
@@ -729,16 +733,28 @@ TelemetryPing.prototype = {
       NetUtil.asyncCopy(istream, ostream,
                         function(result) {
                           self.finishTelemetrySave(Components.isSuccessCode(result),
                                                    ostream);
                         });
     }
   },
 
+  getFlashVersion: function getFlashVersion() {
+    let host = Cc["@mozilla.org/plugin/host;1"].getService(Ci.nsIPluginHost);
+    let tags = host.getPluginTags();
+    
+    for (let i = 0; i < tags.length; i++) {
+      if (tags[i].name == "Shockwave Flash")
+        return tags[i].version;
+    }
+    
+    return null;
+  },
+
   /** 
    * Remove observers to avoid leaks
    */
   uninstall: function uninstall() {
     this.detachObservers()
     if (this._hasWindowRestoredObserver) {
       Services.obs.removeObserver(this, "sessionstore-windows-restored");
       this._hasWindowRestoredObserver = false;

--- a/toolkit/components/telemetry/tests/unit/test_TelemetryPing.js
+++ b/toolkit/components/telemetry/tests/unit/test_TelemetryPing.js
@@ -14,16 +14,17 @@ Cu.import("resource://gre/modules/Lightw
 
 const PATH = "/submit/telemetry/test-ping";
 const SERVER = "http://localhost:4444";
 const IGNORE_HISTOGRAM = "test::ignore_me";
 const IGNORE_HISTOGRAM_TO_CLONE = "MEMORY_HEAP_ALLOCATED";
 const IGNORE_CLONED_HISTOGRAM = "test::ignore_me_also";
 const ADDON_NAME = "Telemetry test addon";
 const ADDON_HISTOGRAM = "addon-histogram";
+const FLASH_VERSION = "1.1.1.1";
 
 const BinaryInputStream = Components.Constructor(
   "@mozilla.org/binaryinputstream;1",
   "nsIBinaryInputStream",
   "setInputStream");
 const Telemetry = Cc["@mozilla.org/base/telemetry;1"].getService(Ci.nsITelemetry);
 
 var httpserver = new nsHttpServer();
@@ -120,17 +121,18 @@ function decodeRequestPayload(request) {
 function checkPayloadInfo(payload, reason) {
   // get rid of the non-deterministic field
   const expected_info = {
     OS: "XPCShell", 
     appID: "xpcshell@tests.mozilla.org", 
     appVersion: "1", 
     appName: "XPCShell", 
     appBuildID: "2007010101",
-    platformBuildID: "2007010101"
+    platformBuildID: "2007010101",
+    flashVersion: FLASH_VERSION
   };
 
   for (let f in expected_info) {
     do_check_eq(payload.info[f], expected_info[f]);
   }
 
   do_check_eq(payload.info.reason, reason);
   do_check_true("appUpdateChannel" in payload.info);
@@ -321,16 +323,50 @@ function dummyTheme(id) {
     name: Math.random().toString(),
     headerURL: "http://lwttest.invalid/a.png",
     footerURL: "http://lwttest.invalid/b.png",
     textcolor: Math.random().toString(),
     accentcolor: Math.random().toString()
   };
 }
 
+// A fake plugin host for testing flash version telemetry
+var PluginHost = {
+  getPluginTags: function(countRef) {
+    let plugins = [{name: "Shockwave Flash", version: FLASH_VERSION}];
+    countRef.value = plugins.length;
+    return plugins;
+  },
+
+  QueryInterface: function(iid) {
+    if (iid.equals(Ci.nsIPluginHost)
+     || iid.equals(Ci.nsISupports))
+      return this;
+  
+    throw Components.results.NS_ERROR_NO_INTERFACE;
+  }
+}
+
+var PluginHostFactory = {
+  createInstance: function (outer, iid) {
+    if (outer != null)
+      throw Components.results.NS_ERROR_NO_AGGREGATION;
+    return PluginHost.QueryInterface(iid);
+  }
+};
+
+const PLUGINHOST_CONTRACTID = "@mozilla.org/plugin/host;1";
+const PLUGINHOST_CID = Components.ID("{2329e6ea-1f15-4cbe-9ded-6e98e842de0e}");
+
+function registerFakePluginHost() {
+  var registrar = Components.manager.QueryInterface(Ci.nsIComponentRegistrar);
+  registrar.registerFactory(PLUGINHOST_CID, "Fake Plugin Host",
+                            PLUGINHOST_CONTRACTID, PluginHostFactory);
+}
+
 function run_test() {
   try {
     var gfxInfo = Cc["@mozilla.org/gfx/info;1"].getService(Ci.nsIGfxInfoDebug);
     gfxInfo.spoofVendorID("0xabcd");
     gfxInfo.spoofDeviceID("0x1234");
   } catch (x) {
     // If we can't test gfxInfo, that's fine, we'll note it later.
   }
@@ -341,15 +377,18 @@ function run_test() {
   // try to make LightweightThemeManager do stuff
   let gInternalManager = Cc["@mozilla.org/addons/integration;1"]
                          .getService(Ci.nsIObserver)
                          .QueryInterface(Ci.nsITimerCallback);
 
   gInternalManager.observe(null, "addons-startup", null);
   LightweightThemeManager.currentTheme = dummyTheme("1234");
 
+  // fake plugin host for consistent flash version data
+  registerFakePluginHost();
+
   Services.obs.addObserver(nonexistentServerObserver, "telemetry-test-xhr-complete", false);
   telemetry_ping();
   // spin the event loop
   do_test_pending();
   // ensure that test runs to completion
   do_register_cleanup(function () do_check_true(gFinished));
- }
+}