Let us suppose you are talking about data in the column A and want to see identifier in the column B.
To the cell B1 enter the formula :
=IF(COUNTIF($A$1:A1,A1)>1,"Duplicate","Unique")
Then copy and paste the formula to all cells B.
See also
http://www.expresscomputeronline.com/20031020/techspace01.shtml>Hi.
>Anybody know of a way, in Excel, to identify duplicate entries in a column ?
>
>Regards,
>Gerard