Mike,

I forgot the mention that the problem is the data where the conditional
formating is on sheet1, but the reference data in column A is actually in
sheet2. They are not on the same sheet.

"Mike H" wrote:

Hi,

Select column a and then

Format|conditional format|formula is

paste this in

=COUNTIF($A$1:$A$10000,A1)1

Pick a colour and click OK

"Cam" wrote:

Hello,

What function do I use in conditional formating?
I have part number on sheet1, I would like the cell the turn different color
if the part number on the cell equal any of the cells on column A. There are
hundred of rows. THANKS