My DB is in Access 2002. The problem now is I have a field called "CE number" that I want to either have a value in the form of (Input Mask: "CE"######? or null) First of all what exactly do I put into input mask? However, I've fiddled around with it a lot. My main problem is this... When "CE number" is empty it responds really funny. Cuz when I check if it is null in an if statement it returns false, but then when I try to MsgBox the "CE Number" it says "Invalid use of null". Example Code: If [CE Number] = Null Then MsgBox "Works" Else MsgBox [CE Number] End If AND when run, it has a problem w/ MsgBox [CE Number] saying it is an invalid use of null. ALSO related when there is an actual value typed in for [CE Number]--something it can even msgbox out. It returns false for If [CE Number]<>Null. In the end all these if statements are just me testing the [CE Number] field. What I want to do is be able to select (in a listbox) the records with matching [CE Numbers]... This selection works with everything unless the [CE Number] field is empty. ANY Ideas or Thought?? THANKS.