Assuming you have a typo in your message and the DOB is in fact in B1 (not
B2), one way is to use a helper column containing this formula which gets the
name and DOB together into one cell:

=A1&" "&TEXT(B1,"yyyymmdd")

If the layout is correct as you show it (instead of the data for one person in
two columns in the same row), you are making your life much more difficult. If
that's the case, you've got to create a list that has the name and DOB for
each person, without blanks.

On Thu, 6 Jan 2005 18:41:01 -0800, "DisperatelySeekingFormula"
om wrote:

Need help with a formula, please, I have a MS Excel spreadsheet with

A1=LAST NAME
B2=DATE OF BIRTH

and I need a formula to show me all instances where the last name AND the
date of birth repeat. I found EXACT formulas, AND formulas, OR formulas, and
even used Conditional Formating with a COUNTIF formula. But non of them are
able to perform a cross comparision or at least I don't know how to enter it
properly.