Let's say I want to look for <Address> <Street>Windsor</Street> </Address> and I do not want to return <Address> <Number>15</Number> <Street>Windsor</Street> </Address> i.e. I am looking for addresses where the Address node does not contain a number tag. I tried things like <Address>(?!Number)</Address> or <Address>.*?(?!Number).*?</Address> but can't quite figure it out :-( Any ideas? TIA eddiec :-)