The role of non-sunlight-related risk factors for squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) of the skin was investigated in a population-based, case-control study conducted among males in Alberta, Canada. In total, 180 SCC and 226 BCC cases and 406 randomly selected male controls, frequency matched by 5-year age groups to the cases, were interviewed by trained personnel using a standardized etiological questionnaire. Data were analyzed using conditional logistic regression techniques. After adjustment for age, skin and hair color, mother's ethnic origin, and sunlight exposure, elevated risks for SCC were seen in subjects exposed to insecticides [odds ratio (OR), highest tertile, 2.8; 95% confidence interval (CI), 1.4-5.6], herbicides (OR, highest tertile, 3.9; 95% CI, 2.2-6.9), and fungicides and seed treatments (OR, highest tertile, 2.4; 95% CI, 1.4-4.0), as well petroleum products, grease, and several other exposures. Elevated risks of BCC were seen in subjects exposed to fiberglass dust (OR, 2.0; 95% CI, 1.0-3.9) and dry cleaning agents (OR, 4.6 95% CI, 1.1-19.7). Prior nondiagnostic X-ray treatment for skin conditions increased risk of both cancers. Although solar UV radiation is known to be the major environmental exposure causing nonmelanocytic skin cancer, results of this study suggest that nonsolar factors may also be important.