Depends on what type of or.
For a simple count of = A or = A
=SUMPRODUCT(--(rng1={"A","B"})
To sum another range with that simple OR
=SUMPRODUCT((rng1={"A","B"})*rng3)
However, if you want, if rng1 = A OR rng2 >5 say, then for a SUM of rng3
meeting these criteria,
=SUMPRODUCT(((rng1="A")+(rng2>5)>0)*rng3)
you have to be careful not to double count here, when rng1 = A and rng2 >5,
hence the > 0 test
See
http://www.xldynamic.com/source/xld.SUMPRODUCT.html for a detailed
explanation.
--
HTH
Bob Phillips
(replace somewhere in email address with gmail if mailing direct)