 <p>LINQ statements return IEnumerable objects, and your method is returning a single Request object. In your case looks like you only need to return the first result of the LINQ statement.</p> <p>Something like:</p> <pre><code> Dim pr = (From r In dc.Request From p In dc.Process.Where(Function(v) v.IdReq = r.IdReq And v.idProcess Is Nothing) Select New {Request = r}).FirstOfDefault Return pr </code></pre>