With the completion of the Human Genome Project, it is likely that genetic testing for susceptibility to a wide range of diseases will increase in society. One venue for such increased testing is likely to be the workplace as employers attempt to protect workers from unhealthy gene-environment interactions, improve productivity, and control escalating health care costs. Past and recent examples of genetic testing in the workplace raise serious concerns that such testing could pose a significant threat to workers' privacy, autonomy, and dignity. Thus, defining the ethically, legally, and socially appropriate and inappropriate uses of genetic testing in the workplace presents a major challenge for occupational health professionals in the years ahead.