A review was made of examples of studies involving both genetic and occupational health risk factors. Five major methodologic approaches were found to be used most frequently: adjustment for confounding by race, ethnicity, and sex; case studies of occupational diseases in genetically susceptible workers; cross sectional studies of the prevalence of disease among genetically differentiated groups; case control studies of the association of genetic characteristics and disease; and family studies of disease aggregations. A 1975 report by the National Academy of Sciences presented 92 genetic disorders which were thought to predispose individuals to pollutant toxicity. Five methodologies have been described for delineating environmental and genetic influences on disease distribution, including twin studies, adoption studies, path analysis, analysis of cultural transmission of risk factors for disease, and studies of specific genotype and disease associations. In most of the studies reviewed, the methodologies for the assessment of the interaction of genetic and occupational risk factors were of limited effectiveness. The author suggests that more powerful techniques need to be utilized for the simultaneous assessment of genetic and occupational risk.