Assume the master data is in Sheet1, cols A to C, viz:
ID#, Last name, First name

In the other sheet where col A (ID#) is blank, assuming Last name, First
name data is running in A2:B2 down

In A2, normal ENTER:
=INDEX(Sheet1!A$2:A$100,MATCH(1,INDEX((Sheet1!B$2: B$100=B2)*(Sheet1!C$2:C$100=C2),),0))

Adapt the Sheet1 ranges to suit the extent of your actuals
--
Max
Singapore
http://savefile.com/projects/236895
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xdemechanik
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"Western_man" wrote:
I need some help, and I am fairly new at this. I have a spreadsheet we fill
out with 4 columns, the first column is blank (ID#), 2nd is Last name (filled
in), 3rd is First name (filled in), forth is Dollars (filled in). I have a
master document with the ID#, Last name, First name, all filled in with data.
I want to compare names in the first document with the master document and
take the ID# from the master and have that entered into the blank ID# column
in the first document. I hope this makes sense...