[en] A brief historical review was made of low-level radiation studies for general populations living around nuclear facilities. In addition, technical and methodological problems were identified and discussed which often arise in all epidemiological studies designed to determine the possible health effects of low-level radiation released from nuclear facilities. Need for extremely large populations for prospective cancer studies was discussed, but accompanying ascertainment difficulties were also emphasized. More epidemiological studies are needed to provide adequate assessment of the potential health hazards of nuclear facilities