Underlying most ethical dilemmas in occupational health practice is the problem of Dual Loyalties where health professionals have simultaneous obligations, explicit or implicit, to a third party, usually a private employer. A literature review was undertaken of case studies of workplace occupational health conflicts, international human rights and ethical codes and strategies for managing dual loyalties, complemented by iterative discussions in an international working group convened to address the problem of Dual Loyalties. Violations of the worker-patient's human rights may arise from: (1) the incompatibility of simultaneous obligations; (2) pressure on the professional from the third party; and (3) separation of the health professional's clinical role from that of a social agent. The practitioner's contractual relationship with the third party is often the underlying problem, being far more explicit than their moral obligation to patients, and encouraging a social identification at the expense of a practitioner's professional identity. Because existing ethical guidelines lack specificity on managing Dual Loyalties in occupational health, guidelines that draw on human rights standards have been developed by the working group. These guidelines propose standards for individual professional conduct and complementary institutional mechanisms to address the problem. Copyright (c) 2005 Wiley-Liss, Inc.