Try using an Advanced Filter...

With your lists in A1: B10, with column headings in the first Row
A1: List_A
B1: List_B

The criteria cells
E1: MatchTest
E2: =COUNTIF($B:$B,A2)=0

The destination cell
C1: List_A

Select columns A:B
<Data<Filter<Advanced Filter
Check: Copy to another location
Check: Unique records only
List range (already selected $A:$B)
Criteria Range: $E$1:$E$2
Copy To: $C$1
Click the [OK] button to create a list of List_A items that are not included
in List_B

Note: the dollar signs and references in the criteria formula

Adjust the range references to suit your situation.

Does that help?

***********
Regards,
Ron

XL2002, WinXP-Pro


"Erik T" wrote:

I want to look in column A and column B for matching part numbers and in
column C have a formula that will display any part number from column A that
is not in column B. I have 3450 part numbers to go through as new numbers are
added every week.

Column A Column B
G0015 G0015
G0092 G0092
G0123V1 G0123V1
G0124 G0124
G0125V2 G0125V2
G0325V3 G0327V1
G0327V1 G0329-2
G0329-2 G0331-1
G0331-1 G0332V1

Thank you,

Erik