Use this Keith
http://www.cpearson.com/excel/NoDupEntry.htm

--
Regards Ron de Bruin
(Win XP Pro SP-1 XL2002 SP-2)
www.rondebruin.nl



"Keith Davis" wrote in message ...
How can I use the validation function of Excel to
restrict the entry of data in a given column to values
that are unique? That is, if a value '48' has already
been entered, then 48 can not be reentered further down
the column.