The development of codes of conduct for transnational corporations is considered, particularly those involving human and labour rights. The issue of compliance with such codes is examined through a detailed consideration of the development and operation of the Sullivan and MacBride Principles. The origin, evolution, and effects of these Principles is considered. Particular attention is paid to institutional and other features surrounding their enforcement, including the use of selective purchasing, shareholder activism, and linkage to government financial incentives. The paper considers what conclusions may be drawn from the operation of these Principles to inform current debates about the effectiveness of corporate codes of conduct.