For all rows in other worksheet where column A = X and column B =
Y, sum column C.

I have tried numerous ways to do this, for instance the other posts'
formulas, however it was still not successful. Any other suggestions?

Sheet 1
Column 1 Column 2 Column 3
Title Date Amount
B Jan-08 10.00
A Feb-08 15.00
A Jan-08 25.00
B Jan-08 10.00

Sheet 2
Column 1 Column 2 Column 3 Column 4
Title Jan-08 Feb-08 Mar-08
A
B

Need forumla to sum if Title in sheet 1 = Title in sheet 2 and Date in sheet
1 = Date in sheet 2, then sum amount in sheet 1.