diff --git a/README.md b/README.md
index 567ac4d..ca287b2 100644
--- a/README.md
+++ b/README.md
@@ -17,7 +17,6 @@ ExecJS supports these runtimes:
   embedded within Ruby
 * [Node.js](http://nodejs.org/)
 * Apple JavaScriptCore - Included with Mac OS X
-* [Mozilla SpiderMonkey](http://www.mozilla.org/js/spidermonkey/)
 * [Microsoft Windows Script Host](http://msdn.microsoft.com/en-us/library/9bbdkx3k.aspx) (JScript)
 
 A short example:
diff --git a/lib/execjs/runtimes.rb b/lib/execjs/runtimes.rb
index 467c226..a26435d 100644
--- a/lib/execjs/runtimes.rb
+++ b/lib/execjs/runtimes.rb
@@ -34,7 +34,8 @@ module ExecJS
     SpiderMonkey = Spidermonkey = ExternalRuntime.new(
       :name        => "SpiderMonkey",
       :command     => "js",
-      :runner_path => ExecJS.root + "/support/spidermonkey_runner.js"
+      :runner_path => ExecJS.root + "/support/spidermonkey_runner.js",
+      :deprecated  => true
     )
 
     JScript = ExternalRuntime.new(