Aircrew and passengers are exposed to low-level cosmic ionising radiation. Annual effectivedoses for flight crew have been estimated to be in the order of 2–5 mSv and can attain75 mSv at career end. Epidemiological studies in this occupational group have beenconducted over the last 15–20 years, usually with a focus on radiation-associated cancer.These studies are summarised in this note. Overall cancer risk was not elevated in moststudies and subpopulations analysed, while malignant melanoma, other skin cancers andbreast cancer in female aircrew have shown elevated incidence, with lesser risk elevations interms of mortality. In some studies, including the large German cohort, brain cancerrisk appears elevated. Cardiovascular mortality risks were generally very low.Dose information for pilots was usually derived from calculation procedures based onroutine licence information, types of aircraft and routes/hours flown, but not on directmeasurements. However, dose estimates have shown high validity when compared withmeasured values. No clear-cut dose–response patterns pointing to a higher risk for thosewith higher cumulative doses were found.Studies on other health outcomes have shown mixed results. Overall, aircrew are a highlyselected group with many specific characteristics and exposures that might also influencecancers or other health outcomes. Radiation-associated health effects have not been clearlyestablished in the studies available so far.