Assuming August08 and Sep08 are sheet names
Enter this in B2 of the sheet having Ids in Col A
=sumproduct(--(August08!A1:A100=A1),(August08!B1:B100)) +
sumproduct(--(Sep08!A1:A100=A1),(Sep08!B1:B100))

Adjust 100 to the last row on each sheet (may be different)

If you have more sheets then you can have Sumproduct on each sheet in a
particular cell and then sum that cell across Sheets
=Sum(Sheet1:Sheet10!A1)

"Chris" wrote:

Hi all,

I've been working on this and can't seem to figure it out.

Here's my data set:

Sept08!
ID Measures
123 0
345 1
545 2
678 2
567 3

August08!
ID Measures
123 0
345 0
545 3
678 1
567 0

What I want to be able to do is Sum the Measures column in Sept08! and
August08!, on a different sheet so that it corresponds with each ID
number: So the result would look like

ID TotalMeasures
123 0
345 1
545 5
678 3
567 3

Any suggestions?

Thanks!

Chris