From the Third National Cancer Survey (TNCS) Interview Study of 7,518 incident cases, lifetime histories of occupations and industries were studied for associations with specific cancer sites and types while controlling for age, sex, race, education, use of cigarettes or alcohol, and geographic location. Lung cancer patients were found more often than expected among several categories including trucking, air transportation, wholesaling, painting, building construction, building maintenance, and manufacturing (furniture, transportation equipment, and food products). Controlling for cigarette smoking did not change these associations. Leukemia and multiple myeloma were associated with sales personnel of both sexes, whereas lymphomas and Hodgkin's disease were excessive among women working in the medical industry. Other associations included rectal cancer with several retail industries; prostate cancer with ministers, farmers, plumbers, and coal miners; malignant melanoma with school teachers; and invasive cervical cancer with women working in hotels and restaurants. Breast cancer patients were more common among women who were teachers or other professionals and who worked in business and finance (even after controlling for education). Many other findings are presented in detailed tables. Results are reported mainly as a research resource for use by other investigators doing work in this field. Suggestions are given for future studies.