Yes.
In the RowSource of your ComboBox:
SELECT YourTable.id, [LastName] & ", " & [FirstName] AS AnyName
FROM YourTable;
Replace 'YourTable' with the name of your table.
'AnyName' can be anything; you can edit it later by clicking on the elipses (...) in the RowSource field of the property sheet for your ComboBox.
ComboBox should have 2 columns, width of the first one should be 0 inches.
Shep