 <p>As of NHibernate 2.1, the <a href="http://nhforge.org/blogs/nhibernate/archive/2008/11/09/nh2-1-0-bytecode-providers.aspx" rel="nofollow noreferrer">proxy factory is pluggable</a>. Here are some proxy providers supported:</p> <ul> <li>Castle.DynamicProxy</li> <li>LinFu</li> <li>Spring.NET</li> </ul> <p>So proxying will be actually out of NHibernate's responsibility, and the answer to this question really depends on the selected proxy factory.</p>