Here is one example... <http://www.ozgrid.com/forum/showthread.php?t=22822>
'-----------------------
Private Sub ComboBox1_Change()
Select Case ComboBox1.Value
Case "A"
With ComboBox2
.Clear
.AddItem "Alan"
.AddItem "Alex"
.AddItem "Andy"
End With
Case "B"
With ComboBox2
.Clear
.AddItem "Bernard"
.AddItem "Bill"
.AddItem "Bob"
End With
Case "C"
With ComboBox2
.Clear
.AddItem "Charlie"
.AddItem "Chris"
.AddItem "Chuck"
.AddItem "Colin"
End With
End Select
End Sub
Private Sub UserForm_Initialize()
With ComboBox1
.AddItem "A"
.AddItem "B"
.AddItem "C"
End With