Hi,
in another column enter

=MATCH(A1,Sheet2!$A$1:$A$30,0)

change sheet2 for the name where you have the members registered to the
conference, where the result is N/A that is a member not registered, you can
sort by N/A to get all the members not registered

"PA" wrote:

Using Excel 2007, I have two worksheets, one has a list of national
membership, including an ID # in column A, the other will contain the similar
information of individual who are attending a national conference. I need to
find those on the membership list who have not registered for the conference.
Thank you