[en] The paper deals with an evaluation of the importance of Finnish freshwater fish as a source of ¹³⁷Cs in the diet. Freshwater fish were analysed for ¹³⁷Cs in 1982. The ¹³⁷Cs concentration factors from water to edible fish were determined for the same year. The evaluation is based on an extensive surface water investigation performed from 1965 to 1967. Along with the continuous fallout monitoring since the beginning of the 1960'es, this material makes it possible to valuate the ¹³⁷Cs levels in surface water right up to the 1980'es. In 1982 the Finns received an average of 90 Bq ¹³⁷Cs from freshwater fish. This dose constitutes a quarter of the ¹³⁷Cs uptake from the total food consumtion in Finland in 1982