Select the range of cells in question. Assume this range is C1:C3000
Goto the menu FormatConditional Formatting
Select Formula Is
Enter this formula in the box on the right:

=COUNTIF(C$1:C$3000,C1)1

Click the Format button
Select the Patterns tab
Select a fill color of your choice
OK your way out.

--
Biff
Microsoft Excel MVP


"Daniel - Sydney" wrote in message
...
Hi

I have Excel 2003.

I have a spreadsheet where column C has over 3,000 item codes, some of
these
are repeated, some more than once.

How do I highlight the codes that are appear more than once in the column.

thanks