A number of researchers have pointed out that less is known about occupational determinants of health in women than in men. The authors examine inventories of ongoing Canadian research and of recent scientific publications in order to identify trends in the approaches used to study women's occupational health (WOH). We also consider conceptual issues in the treatment of the sex and gender of subjects. We observe that women have been the subject of relatively few investigations of occupational health in the natural or biomedical sciences and that studies of WOH have concentrated on the health care professions and on psychosocial stressors, with a deficit in toxicological and physiological studies. We use recent studies of mercury exposure in chloralkali process plants and of musculoskeletal disorders among office workers to provide specific examples of problems in conceptualizing WOH. We propose that WOH be studied more often, especially by researchers in the natural and biomedical sciences, and that such studies include both women and men, where possible, and consider the complex relationships of gender and sex to the pathways involved. More interdisciplinary research would facilitate this process, since social researchers have tended to focus more on gender/sex issues. Our findings demonstrate that it is necessary to explore the implications of using sex routinely as an explanatory variable in occupational health research and to increase emphasis on the mechanisms involved in any sex or gender differences sought or found. From an equity perspective, it is also important to situate biological sex differences so as to prevent them from being used erroneously to justify job segregation or inequitable health promotion measures.