Thanks It works great.
I also added few more arrays to it and incorporated it into a macro.

but the problem is speed.
there are 12000 records

anyway to do it quicker?

"Bob Phillips" wrote:

Pt this in C2 and copy down

=IF(SUMPRODUCT(--($A$2:A2=A2),--($B$2:B2=B2))1,"","Unique")

--
HTH

Bob Phillips

(remove nothere from email address if mailing direct)

"flow23" wrote in message
...
I have two columns..

ID MONTH
100 Jan-04 Unique
200 Jan-04 Unique
200 Jan-04
300 Feb-04 Unique
300 Feb-04
300 Feb-04


what I want is a macro to write "Unique" in the third column if " ID " is
there only once in a month. and in case its there more than once in the
same
month. only one "Unique" in the third column


any help apprecaited