conditional formating can not be used between sheets at least in 2003 Excel.
if you are looking names which are exactly alike
adding a helper column and using =countif(Sheet2!A:A),A1) will tell you if
there is a duplicate to what is in A1 in Sheet 2 Column A

"LC in Boston" wrote:

Am trying to figure the most efficient way to compare two spreadsheets that
will have customer/account information -- trying to ID duplicate names
between the two sheets. Looked on Help and am still not sure if conditional
formatting is the way to go?