The one at www.rustemsoft.com works very well but you do have to pay for it, $35.00, but it does more than just single column comboboxes. It also does multicolumn combo boxes, datepicker, button control on the grid and some others. I found a number of free, single column comboboxes when I did a web search for datagrid combobox. Actually they were projects that showed how to use the standard vb.net combo box in a datagrid.