Thanks everybody,

I used a combination of Tom's and Rob's suggestions.
like this:

Private Sub UserForm_Initialize()
Me.ScrollBars = fmScrollBarsVertical
Me.ScrollHeight = 400
Me.Height = 0.3 * Me.Height
End Sub

A new problem occurred however.

When the form pops up it focuses on the vertical end of the form, where I
would like the form to focus on the vertical top of the form.
Has this anything to do with a command button, which is at the end of the
form? This button has the focus (automatically) because I want users to be
able to push Enter to close the form?

greets,

Sybolt