Try something like

Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Cells.Count 1 Then ' In XL2007, use CountLarge, not Count
Exit Sub
End If
If Target.Text = vbNullString Then
Target.Font.ColorIndex = xlColorIndexAutomatic
Exit Sub
End If
If Application.WorksheetFunction.CountIf( _
Me.Range("A1:A100"), Target.Text) 1 Then
Target.Font.ColorIndex = 3 ' red
Else
Target.Font.ColorIndex = xlColorIndexAutomatic
End If
End Sub


--
Cordially,
Chip Pearson
Microsoft Most Valuable Professional
Excel Product Group
Pearson Software Consulting, LLC
www.cpearson.com
(email on web site)




wrote in message
...
For various reasons, I would prefer to use vba as opposed to
conditional formatting for my worksheet. If a duplicate value (in
this case, lengthy text entries) exists, change the font color to
blue. I can successfully write the macro for it but again, I would
prefer that it fire automatically on the Worksheet Selection Change
and I just can't figure how to make that work.

"=COUNTIF($D$1:$D$1000,D1)1"

Any assistance greatly appreciated as always.