Try the following formula that needs to be confirmed with
CONTROL+SHIFT+ENTER...

=SUM(IF(FREQUENCY(IF((LEN(A1:A10)0)*(B1:B10=C1),M ATCH(A1:A10,A1:A10,0),"
"),IF((LEN(A1:A10)0)*(B1:B10=C1),MATCH(A1:A10,A1: A10,0),""))0,1))

....where C1 contains the 'product' of interest.

Hope this helps!

In article ,
"markx" wrote:

Hello everybody,

I would like to count duplicate entries on my excel sheet, but only if a
certain value is existing in a parallel column, same row. For exemple, there
could be 200 duplicate entries in the whole column A, but only 50 of them
would be in relation to the Product MMM (specified in column B). Other
duplicates would concern Products JJJ or PPP.

Do you know any method of counting duplicates (other than manual:-) based on
a condition that could deal with my problem?

Thanks a lot for your help on this,
Mark

P.S: If there would be no condition needed (simple counting of duplicates),
we could use the following ARRAY formula (found on Chip Pearson's page
(http://cpearson.com/excel/duplicat.htm) counting unique entries:

=SUM(IF(FREQUENCY(IF(LEN(Range1)0,MATCH(Range1,Ra nge1,0),""),
IF(LEN(Range1)0,MATCH(Range1,Range1,0),""))0,1))

and then substract it from the total count. However, including condition in
there (related to another column) is too hard for me!