Maybe

=COUNTIF($C:$C,C4)+COUNTIF('[737.xls]Sheet1'!$C:$C,C4)

Regards
Rowan

"Davor ®upaniæ" wrote:

How to merge (expand) range criteria for COUNTIF outside the sheet1.

=COUNTIF(C:C+[737.xls]Sheet1!$C:$C;C4)

That is not working.

How to fix that?