If you want to make your NSTableView a source for a drag and drop operation, you need to implement- (BOOL) tableView: (NSTableView *) tableView writeRowsWithIndexes: (NSIndexSet *) rowIndexes toPasteboard: (NSPasteboard *) pboard;in your table view data source (and don't forget to hook up the datasource if you use bindings to populate the tableview)(Thanks to Rob Rix for updating this with more modern API)