OBJECTIVE--To assess whether occupational exposure among commercial airline cabin attendants are associated with risk of cancer. DESIGN--Record linkage study. SETTING--Finland. SUBJECTS-1577 female and 187 male cabin attendants who had worked for the Finnish airline companies. MAIN OUTCOME MEASURE--Standardised incidence ratio; expected number of cases based on national cancer incidences. RESULTS--A significant excess of breast cancer (standardised incidence ratio 1.87 (95% confidence interval 1.15 to 2.23)) and bone cancer (15.10 (1.82 to 54.40)) was found among female workers. The risk of breast cancer was most prominent 15 years after recruitment. Risks of leukaemia (3.57 (0.43 to 12.9)) and skin melanoma (2.11 (0.43 to 6.15) were not significantly raised. Among men, one lymphoma and one Kaposi's sarcoma were found (expected number of cases 1.6). CONCLUSIONS--Although the lifestyle of cabin attendants is different from that of the reference population--for example, in terms of social status and parity--concentration of the excess risks to primary sites sensitive to radiation suggests that ionising radiation during flights may add to the cancer risk of all flight personnel. Otherwise the lifestyle of cabin attendants did not seem to affect their risks of cancer. Estimates of the effect of reproductive risk factors only partly explained the increased risk of breast cancer. If present estimates of health hazards due to radiation are also valid for cosmic radiation, then the radiation doses of cabin attendants seem too small to account entirely for the observed excess risk.