A guide to object equality in .NET (part 4) 20 May 2011 by Jason Duffett tech 1 min read The IEquality interface. http://msdn.microsoft.com/query/dev10.query?appId=Dev10IDEF1&l=EN-US&k=k%28%22SYSTEM.IEQUATABLE%601%22%29;k%28TargetFrameworkMoniker-%22.NETFRAMEWORK%2cVERSION%3dV4.0%22%29;k%28DevLang-CSHARP%29&rd=true Update answer at http://stackoverflow.com/questions/798121/date-vs-datetime