Check to see if there's something numeric in that D range:

=SUMPRODUCT(--($B$2:$B$268=$U277),
--(isnumber($d$2:$d$268),
--(MONTH($D$2:$D$268)=1),
($K$2:$K$268))

Phil_S wrote:

I have a worksheet in which I am tring to sum the data based upon a code
range, a date range and cost range. However when I enter this formula it sums
the data from blank cells into the cell i wish to sum all the costs for
January.

=SUMPRODUCT(--($B$2:$B$268=$U277),--(MONTH($D$2:$D$268)=8),($K$2:$K$268))

Is there any way around this?

--

Dave Peterson