=SUMPRODUCT(--(A1:A5="Monkey"),--(B1:B5<--"1/1/2009"),C1:C5)


"mokihi" wrote:

I would like to use a sumif function to count the values in column C if
Column A is a "Monkey" and Column B is "before 1/1/2009".

Thanks in advance


A B C
Dog 6/4/2007 0.456
Cat 5/4/2005 0.5454
Monkey 12/1/2007 0.33442
Monkey 12/1/2009 0.3344
Monkey 7/1/2009 0.9458