Assume Sheet1 column headers are plain text, while dates in Sheet2 are true
dates, try this *array* formula:

=COUNT(IF(TEXT(Sheet2!D1:D20,"mmmm")=C1,Sheet2!D1: D20))

--
Array formulas are entered using CSE, <Ctrl <Shift <Enter, instead of the
regular <Enter, which will *automatically* enclose the formula in curly
brackets, which *cannot* be done manually.
--
HTH,

RD
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Please keep all correspondence within the Group, so all may benefit!
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"MHY" wrote in message
...
On sheet 1 I have the months across the top row and lets say that the
month
of March is in c1. On sheet 2 I have a column (d1:d20) with many dates,
and
I want to count the number of dates in the month of March.
I think it would go something like this,
=countif(month(sheet 2(d1:d20)),sheet 1(c1))
I may not have all of the () in the right place but hope you get the idea.
Thansk