Select the code I gave you in my previous message
Hit Ctrl-C (copy)
Get back to Excel Window
Right-click on the tab with your worksheet name
Select "Code"
Hit Ctrl-V (Paste)
Get back to Excel Window
Try entering values in column B

HTH
--
AP

"Abby" a écrit dans le message de
...
Maybe I should have gone to the "new users" link. I don't know what you
mean
by "worksheet code".

"Ardus Petus" wrote:

Paste the following code into your Worksheet's code:

'----------------------------------
Private Sub Worksheet_Change(ByVal Target As Range)
'Adjust next constant to your own needs
Const myColumn As String = "B"
Dim rng As Range
Dim Found As Range

Set rng = Columns(myColumn)
If Intersect(Target, rng) Is Nothing Then Exit Sub
Set Found = rng.Find(Target.Value)
If Found.Address < Target.Address Then MsgBox ("Duplicate code")
End Sub
'-----------------------------------

HTH
--
AP

"Abby" a écrit dans le message de
...
I want a warning to appear when I enter a duplicate code.

"Ardus Petus" wrote:

Do you want a warning to appear upon input of a duplicate code?

Or else, do you want to check for duplicates in existing codes?

Cheers,
--
AP

"Abby" a écrit dans le message de
...
I am creating a work sheet for CPT codes, showing what was billed
and
what
was allowed by the insurance company. Codes are sorted in
numerical
order.
How do I make sure that I don't repeat one?