We investigate factors affecting the number of outside directorships held by CEOs. CEOs of firms with growth opportunities hold fewer outside directorships than CEOs of firms consisting primarily of assets-in-place. We find evidence consistent with CEOs holding more outside directorships as they transfer decision rights to their eventual successors. We also find that when employees (not necessarily CEOs) of two different firms sit on each other's boards, CEOs hold more outside directorships, suggesting CEO participation bonds the relationship between the two firms. We find little evidence that outside directorships represent unchecked perquisite consumption on the part of CEOs.