=SUMPRODUCT(--(MONTH(A2:A100)="1"),--(B2:B100="Vendor"),C2:C100))

Also you may want to look at pivot tables. More info he
http://www.cpearson.com/excel/pivots.htm

Dave
--
Brevity is the soul of wit.


"FPJ" wrote:

Hi,

I have a worksheet that look like this:

A B C
1/2/2006 Vendor $150
1/5/2006 Tooling $210
1/28/2006 Vendor $60
2/12/2006 Vendor $190
2/22/2006 Tooling $200
3/14/2006 Vendor $153

I'd like to get the total $ cost of vendor in the month of Jan.
Please help on how to write the formula.

Thanks in advance.