We have two aims in this paper. The first is negative: to demonstrate the problems in Bernard Gert's account of common morality, in particular as it applies to professional morality. The second is positive: to suggest a more satisfactory explanation of the moral basis of professional role morality, albeit one that is broadly consistent with Gert's notion of common morality, but corrects and supplements Gert's theory. The paper is in three sections. In the first, we sketch the main features of Gert's account of common morality in general. In the second, we outline Gert's explanation of the source of professional moral rules and demonstrate its inadequacy. In the third section, we provide an account of our own collectivist needs-based view of the source of the role-moral obligations of many professional roles, including those of health care professionals.