 <p>If the backing field isn't static, how are you going to obtain an instance for that field when you use it in a static property accessor? Remember that the <code>static</code> modifier on a member means that this member is associated with the <em>type itself</em>, rather than with a particular <em>instance</em> of that type. For a static property to work, it has to have a backing field that is itself static so that it can be implemented accordingly.</p> <p>It's for the same reason that you can't access any non-static members within static methods without having an instance to work with.</p>