Add Namespace to Element
using System; using System.Linq; using System.Xml.Linq; using System.Collections.Generic; class Program/*from ww w . j av a2 s . com*/ { static void Main(string[] args){ XNamespace nameSpace = "http://www.book2s.com"; XElement xBookParticipants = new XElement(nameSpace + "BookParticipants", new XElement(nameSpace + "BookParticipant", new XAttribute("type", "Author"), new XElement(nameSpace + "FirstName", "Joe"), new XElement(nameSpace + "LastName", "Ruby")), new XElement(nameSpace + "BookParticipant", new XAttribute("type", "Editor"), new XElement(nameSpace + "FirstName", "Ewan"), new XElement(nameSpace + "LastName", "Buckingham"))); Console.WriteLine(xBookParticipants.ToString()); } }