Risk factors for superficial and invasive bladder cancer were examined in a case-control study of 470 cases identified in 1967-68 in the Brockton and Boston Standard Metropolitan Areas (MA, United States) and of 500 population-based controls. Histologic specimens were reviewed and classified as superficial or invasive, following a standardized protocol. The tobacco-associated risk for superficial bladder cancer was odds ratio (OR) = 2.6 (95 percent confidence interval [CI] = 1.7-4.1) and the risk for invasive bladder cancer was OR = 1.7 (CI = 1.1-2.5). For subjects less than 60 years of age, the risks were greater for invasive tumors (OR = 4.3, CI = 1.2-15) than for superficial tumors (OR = 2.0, CI = 0.9-4.2), but this pattern for tobacco use was not found in older subjects. A strong trend of increased risk with increased amount of cigarettes smoked was shown only for invasive bladder tumors. No clear pattern of excess risk for invasive bladder tumors was seen for age at first use and years since last use of tobacco. The risk associated with occupational exposure to aromatic amine bladder carcinogens was OR = 1.7 (CI = 0.8-3.3) for superficial and OR = 1.5 (CI = 0.8-3.0) for invasive bladder cancer. For subjects less than 60 years of age, the risks were greater for invasive (OR = 12.0, CI = 2.1-65) than for superficial tumors (OR = 4.3, CI = 0.8-24), but this pattern for occupational exposure was not found in older subjects.(ABSTRACT TRUNCATED AT 250 WORDS)