Why not create a field PrimaryPhone and check it? John

I handle this in my form by running an update query when isPrimary is checked that updates every number for the customer that is NOT the number selected to isPrimary = false. So if a customer has numbers A, B, C, and D, and the user checks C as 'IsPrimary,' then an update query sets A, B, and D to 'IsPrimary' to false.

@John Davy - Not sure what you are saying...what I have is a continuous form that has phone types like 'Cell', 'Home', 'Office'...and so forth - I have a checkbox (Yes/No) labeled as "IsPrimary" and I only want one of those checked at any one time. That way, I can query and/or pull the 'Primary' number into another phone field in another form/table.

@Michael Craytor - That sounds good, but my SQL skills are a little rusty and am having trouble picturing what the syntax would be...or is this in VBA? Sorry, I sound like a noob but I haven't had to go too deep into SQL over the last 10 years (and then zero SQL over the past year as I'm currenlty 'semi-retired' but am picking up a few freelance jobs here and there).

Thanks in Advance!!