The content of radioactive caesium isotopes emitting beta radiation was studied in daily food rations analysed in diets of working-class and non-working-class families from food products from the regions of Olsztyn, Poznań, Lublin, Warsaw and Wrocław in 1987 and 1988. In 1987 the highest level of radioactive caesium was found in the food rations in Olsztyn, and the lowest in the rations in Poznań (3.32 and 0.65 Bq/kg respectively). In 1988 higher radio-caesium content was found in rations composed according to the data on the diet consumed daily in non-working-class families. In that case the highest content was in the daily food ration composed in Warsaw--2.35 Bq/kg, and lowest in Poznań--1.19 Bq/kg. In the daily food rations of working-class families about one half of that value was found. The calculated mean values of both analysed rations were: 1.35 for Olsztyn, 0.89 for Poznań, and 1.86 Bq/kg for Warsaw. The calculated mean value of the contamination with radioactive caesium was in 1988 0.93 Bq/kg for the rations in working-class families (in 1987 it was 1.80 Bq/kg).