Assuming the serial numbers are in column A on both sheets, try this
in B1 of Sheet2:

=IF(ISNA(MATCH(A1,Sheet1!A$1:A$19000,0)),"No","Yes ")

Copy this down your 3000 rows.

You can then apply autofilter to column B to select just the Yes
returns.

Hope this helps.

Pete

On May 12, 12:10*pm, PauloG wrote:
I have 2 sheets with serial numbers on them. Sheet 1 has over 19,000 serial
numbers on it and Sheet 2 has 3,000. Sheet 1 also has addresses attached to
them and Sheet 2 is simply the serial numbers. I want to compare these two
sheets and see which Serial Numbers on Sheet 2 appear in Sheet 1. I have
tried a few SUMIF and COUNTIF formulas but to no avail. I am desperate so any
would be appreciated!