By its very nature, practice and intended applications, the profession of occupational toxicology has individual and collective responsibilities related to the design, conduct, interpretation and extrapolation of laboratory and controlled human clinical studies in order to determine the potential for industrial xenobiotics to produce adverse effects. The implications for health-related adverse effects in the workplace, and in the domestic and general environment carries many and various responsibilities for the toxicologist which are related to multiple and wide-ranging ethical issues. This review presents and discusses some of the major areas where the occupational toxicologist may experience potential ethical problems related to the conduct of routine professional activities. Emphasis is placed on the design, conduct, interpretation and reporting of laboratory studies; animal welfare; regulatory activities; human clinical volunteer studies; roles and responsibilities in defining workplace safety and protective measures; malpractices in various disciplines and work practices; misconduct in publication; and codes of ethical behavior. Copyright © 2005 John Wiley & Sons, Ltd.