=SUMPRODUCT(B1:B4,--(HOUR(A1:A4)=Sheet2!A1))/SUMPRODUCT(--(HOUR(A1:A4)=Sheet2!A1))
Adjust the range for the "cell in another worksheet" to suit.

Regards,
Fred

"Ryan Hicks" wrote in message
...
I need help coming up will a function that will average a range in one
column
based on if the hours match. Here is my set up.

-------A-------B
1.....09:21....12
2.....09:46....24
3.....09:57....17
4.....10:04....22

I need to average column B if column A's hour is the same as the hour in a
cell in another worksheet.