 <p>Modern, LINQ-based way (old-fashined C-programmers can turn in one's grave):</p> <pre><code>List&lt;Byte&gt; list = new List&lt;byte&gt;() { 0x01, 0x5F }; var output = list.Select(x =&gt; (int)x) .Reverse() .Aggregate((x, y) =&gt; (int)0x100 * y + (int)x); </code></pre>