If the data in A1 & B1 matches as per the criteria
It would have been better if you told us what the criteria are.
Try something like this:
=SUMPRODUCT(--(A1:A10="criteria1"),--(B1:B10="criteria2"),C1:C10)
Better to use cells to hold the criteria:
E1 = criteria1
F1 = criteria2
=SUMPRODUCT(--(A1:A10=E1),--(B1:B10=F1),C1:C10)
If you're using Excel 2007:
=SUMIFS(C1:C10,A1:A10,"criteria1",B1:B10,"criteria2")
=SUMIFS(C1:C10,A1:A10,E1,B1:B10,F1)
In all of the above formulas if criteriaN is a NUMBER then don't use the
quotes.
=SUMPRODUCT(--(A1:A10=10),--(B1:B10=0),C1:C10)