Cancer mortality patterns were examined according to occupation for adult white males in Massachusetts using 1971 and 1973 death certificates. A total of 62 malignancy categories were investigated for each of 397 occupational categories using an age standardized mortality odds ratio approach. The occupational categories were coded into groups likely to have similar exposure to environmental carcinogens and into 70 grouped categories of similar occupations. Six large employers were named on the death certificate with sufficient frequency to permit analysis. These occupations included truck drivers, painters, machinists, automobile mechanics, plumbers, cooks, fishermen, heated metal workers, sheet metal workers, brick masons, stone masons, and tile setters. Occupations found to be at excess risk of lung cancer included agricultural scientists, mechanics and repair workers of air conditioning, heating, and refrigeration appliances, building managers, superintendents, and compositors and typesetters. Workers in the printing trade showed significant excess of cancer of the buccal cavity and pharynx. Excess cancer of the prostate was found in compositors and typesetters, painters, and welders, occupations that have potential exposure to cadmium (7440439). There were strong correlations between lung cancer rates and occupations having potential exposure to asbestos (1332214) such as various construction trades, mechanics in vehicle repair shops, custodial, maintenance and cleaning type jobs, and shops for repairing air conditioners, heating, and refrigeration appliances. The association of cancers of the trachea, bronchus, and lung and occupations with potential exposure to cleaning chemicals was evident in custodial, maintenance, and cleaning workers. Cancers of the buccal cavity, pharynx, esophagus, biliary passages, and liver were excessive in bar workers, cooks, and chefs; these occupations had potential exposure to the etiologic agents alcohol and cigarette smoke.