 <p>You can do this using an attribute on your wcf service:</p> <pre><code>[ServiceBehavior(InstanceContextMode = InstanceContextMode.Single)] class MySingleton : ... {...} </code></pre> <p>With this your WCF service has a single instance, that is used by all callers.</p> <p>For details see: <a href="http://msdn.microsoft.com/en-us/magazine/cc163590.aspx" rel="nofollow">http://msdn.microsoft.com/en-us/magazine/cc163590.aspx</a></p>