This study examines the estimated risk of bladder cancer associated with various occupations among 1,465 cases identified in Orange County, California, during 1984-1988. The annual age-adjusted incidence rate per 100,000 population in Orange County was similar to that of the Surveillance, Epidemiology, and End Results Program of the National Cancer Institute: 25.7 in males and 6.2 in females. Cases were compared with a sample of Orange County residents relative to broad category of current occupation, adjusted for age and cigarette smoking. The estimated relative risks were significant for males in machine trades (relative risk (RR) = 2.69, 95% confidence interval (CI) 1.24-5.82) and processing occupations (RR = 5.77, 95% CI 1.43-23.27) and for females in machine trades (RR = 8.34, 95% CI 1.14-61.17) and homemakers (RR = 5.37, 95% CI 2.40-11.99) as compared with individuals of the same sex in professional, technical, and managerial occupations.