Hate having to crack open the InfoPath file just to get the appropriate namespaces for your XPath queries? System.Xml.XmlNamespaceManager nsm = ...; // ...nsm.AddNamespace(''my'', ''http://schemas.microsoft.com/office/infopath/2003/myXSD/2006-04-20T16:26:21''); Use this little gem instead of the second line ...