Set the Increment to 0.

        If CheckBox1.Checked Then
            NumericUpDown1.ReadOnly = True
            NumericUpDown1.Increment = 0
        Else
            NumericUpDown1.ReadOnly = False
            NumericUpDown1.Increment = 1
        End If

>Hello,
>I have a couple of NumberUpDown controls on my form that I designated read-only. However, I can still scroll up and down. Is there a way to truly make it read-only? TIA!
>
>-MAC