=SUMPRODUCT(--(A1:A4="a"),--(B1:B4="x"),C1:C4)

See http://www.xldynamic.com/source/xld.SUMPRODUCT.html for an explanation


--

HTH

RP
(remove nothere from the email address if mailing direct)


"Dirk" wrote in message
...
I need a formula like SUMIF but the query should be in TWO colons.

A B C
1 a x 2
2 a x 1
3 b x 1
4 b y 3

if A1:A4="a" AND B1:B4=x then SUM C1:C4