diff --git a/browser/components/preferences/privacy.js b/browser/components/preferences/privacy.js
index 8c4f1306d4f..9ebdc844e5e 100644
--- a/browser/components/preferences/privacy.js
+++ b/browser/components/preferences/privacy.js
@@ -161,7 +161,7 @@ var gPrivacyPane = {
    * network.cookie.cookieBehavior
    * - determines how the browser should handle cookies:
    *     0   means enable all cookies
-   *     1   means allow cookies from the "originating" server only; see
+   *     1   means reject third party cookies; see
    *         netwerk/cookie/src/nsCookieService.cpp for a hairier definition
    *     2   means disable all cookies
    * network.cookie.lifetimePolicy
@@ -173,31 +173,51 @@ var gPrivacyPane = {
 
   /**
    * Reads the network.cookie.cookieBehavior preference value and
-   * enables/disables the "Keep until:" UI accordingly, returning true
+   * enables/disables the rest of the cookie UI accordingly, returning true
    * if cookies are enabled.
    */
   readAcceptCookies: function ()
   {
     var pref = document.getElementById("network.cookie.cookieBehavior");
+    var acceptThirdParty = document.getElementById("acceptThirdParty");
     var keepUntil = document.getElementById("keepUntil");
     var menu = document.getElementById("keepCookiesUntil");
 
-    // anything other than "disable all cookies" maps to "accept cookies"
+    // enable the rest of the UI for anything other than "disable all cookies"
     var acceptCookies = (pref.value != 2);
 
-    keepUntil.disabled = menu.disabled = !acceptCookies;
+    keepUntil.disabled = menu.disabled = acceptThirdParty.disabled = !acceptCookies;
     
     return acceptCookies;
   },
 
+  readAcceptThirdPartyCookies: function ()
+  {
+    var pref = document.getElementById("network.cookie.cookieBehavior");
+    return pref.value == 0;
+  },
+
   /**
    * Enables/disables the "keep until" label and menulist in response to the
    * "accept cookies" checkbox being checked or unchecked.
    */
   writeAcceptCookies: function ()
   {
-    var checkbox = document.getElementById("acceptCookies");
-    return checkbox.checked ? 0 : 2;
+    var accept = document.getElementById("acceptCookies");
+    var acceptThirdParty = document.getElementById("acceptThirdParty");
+
+    // if we're enabling cookies, automatically check 'accept third party'
+    if (accept.checked)
+      acceptThirdParty.checked = true;
+
+    return accept.checked ? (acceptThirdParty.checked ? 0 : 1) : 2;
+  },
+
+  writeAcceptThirdPartyCookies: function ()
+  {
+    var accept = document.getElementById("acceptCookies");
+    var acceptThirdParty = document.getElementById("acceptThirdParty");
+    return accept.checked ? (acceptThirdParty.checked ? 0 : 1) : 2;
   },
 
   /**
diff --git a/browser/components/preferences/privacy.xul b/browser/components/preferences/privacy.xul
index daa4880a5b2..7f80c9afb0a 100644
--- a/browser/components/preferences/privacy.xul
+++ b/browser/components/preferences/privacy.xul
@@ -142,6 +142,12 @@
                 label="&cookieExceptions.label;" accesskey="&cookieExceptions.accesskey;"
                 preference="pref.privacy.disable_button.cookie_exceptions"/>
       </hbox>
+      <checkbox id="acceptThirdParty" label="&acceptThirdParty.label;" class="indent"
+                preference="network.cookie.cookieBehavior"
+                accesskey="&acceptThirdParty.accesskey;"
+                onsyncfrompreference="return gPrivacyPane.readAcceptThirdPartyCookies();"
+                onsynctopreference="return gPrivacyPane.writeAcceptThirdPartyCookies();"/>
+
       <hbox id="keepRow">
         <hbox id="keepBox" align="center" class="indent">
           <label id="keepUntil"