Well, you've missed the sheet name from the second condition, so maybe
it should be:

=SUMPRODUCT(--(MONTH('2008'!B3:B2000)=1),--(YEAR('2008'!
B3:B2000)=2009))

Hope this helps.

Pete

On Jul 31, 11:38*am, Tina wrote:
=SUMPRODUCT(--(MONTH('2008'!B3:B2000)=1),--(YEAR(B3:B2000)=2009))

Hi all, *I am using the above, but am getting #VALUE!

The format the date is typed in, in the main data sheet, is "05 January
2009", but I have also tried 05/01/2009 but to no avail. *Can anyone say
where I am going wrong?
Thanks
Tina