Adam
Ivan Moala's response to "compare column data - Gary 2/14/00" below, should get you started. Cells that are not grayed in col A do not appear in col B. Now just clear or whatever rather than color, and you will have a list of the differences.
Mark
Adam
If you prefer to do this with a worksheet formula instead of a macro, the following should do it.
If your two lists are in column A (say, A1:A10) and in column B, the following array formula will give the entries in column B that do not appear in column A.
=IF(COUNTIF($A$1:$A$10,B1)=0,B1,)
You might find it helpful to look at :-
http://www.cpearson.com/excel/duplicat.htm
Celia