It should work. My guess might be that you originally set up the Names
"Prod" and "Vol" to include 258 rows, but never redefined these ranges as you
added more data?

Hit CTRL-F3
Select "Prod"
Verify that it refers to the entire range you want to include (900+ rows)
Do the same with "Vol"

HTH
Elkar



"ATL_Gabriel" wrote:

=SUM(IF(Prod={"Product_12","Product_100"},Vol,0))
This funtion array fails to return the correct sum. The product name (Prod)
column and value (Vol) column reprsents about 900 rows. The fomula returns
the wrong sum when this happens. If I reduce rows to 258 or less the correct
sum is returned. Is there a limitation when using arrays.