The risk of renal cell cancer among those in occupations with potential for petroleum exposure was evaluated in a large population-based case-control study. Overall there was little difference between the cases and control groups in the proportion of persons with petroleum-related employment (odds ratio = 1.0). Among gasoline station attendants, a slight upward trend in risk was observed with increasing duration of employment. The significance of this association is not clear, but further research is needed in light of recent animal findings linking gasoline exposure to renal cancer.