Something like the below..

Private Sub TextBox1_Exit(ByVal Cancel As MSForms.ReturnBoolean)
If WorksheetFunction.CountIf(Sheets("Sheet1").Range(" D:D"), _
TextBox1.Text) 0 Then
TextBox1.Text = "": MsgBox "Already Exists": Cancel = True
End If
End Sub

If this post helps click Yes
---------------
Jacob Skaria


"Jock" wrote:

Users can input numeric values into Textbox 1 on userform1.
Upon exit from the textbox, how do I check Sheet1, column D for the same
value (ie a duplicate)?
tia
--
Traa Dy Liooar

Jock