Hi

one way of doing it would be to use array's this is fine if your
options will not need to change on a regular basis

Private Sub ComboBox2_Change()

Select Case ComboBox2.Value

Case "Wheels"

ComboBox3.List = Array("bus", "car", "bicycle")

Case "No Wheels"

ComboBox3.List = Array("walk", "swim", "run")

End Select

End Sub

hope this helps

S