Crossposted. It is considered rude to post the same question to multiple boards UNLESS you provide a link to the other board.

The first is easy. Just compare to nothing.

[vba]If Cells(1,2).value <> "" then
Combobox1.Additem Cells(1,2).value
[/vba]
2. You will have to compare the contents of each combox with the item to add. If there are a lot of items to add, this will bog down after half way.

You could use a Collection to create your unique items and store the range of items for each combobox.