 <p>protobuf.net has to maintain compatibility with the protobuf binary format, which is designed for the Java date/time datatypes. No <code>Kind</code> field in Java -> No <code>Kind</code> support in the protobuf binary format -> <code>Kind</code> not transferred across the network. Or something along those lines.</p> <p>As it turns out, protobuf.net encodes the <code>Ticks</code> field (only), you'll find the code in <a href="http://code.google.com/p/protobuf-net/source/browse/trunk/protobuf-net/BclHelpers.cs#135" rel="nofollow"><code>BclHelpers.cs</code></a>.</p> <p>But feel free to add another field in your protobuf message definition for this value.</p>