The whole-life occupational histories of 1,030 patients (812 men and 218 women) with papilloma and carcinoma of the bladder were analyzed. Bladder tumor patients whose smoking habits were known were matched with surgical control patients (340 men and 50 women) and with other cancer patients (312 men and 39 women) for sex, age decade, habitat, and smoking habits. Numbers in the matched pairs in different occupations (Registrar General's Classification of Occupations, 1966) were compared for predominant occupation, occupied at any time, and for 20 years or more. Results were confirmed from the distribution of occupations among the unmatched bladder tumor patients (429 men and 161 women) and from a comparison of expected and observed numbers in different occupations for the patients living in the City of Leeds (519 men and 146 women). The results confirmed the risk to dye workers and revealed risks to medical workers (mainly nurses), to tailors, tailors' pressers, and some groups of engineers and textile workers (associated with long-term employment only), and possibly also to hairdressers and tailors' cutters. Tumor occurred at younger ages in men who had been employed as dye workers, tailors' cutters (P = < 0.025), or hairdressers (not significant), but not in the other suspect occupations. Over 20% of bladder tumors in men in this series could be occupational in origin.