The occurrence of mirids on wheat in Finland and Poland is described and the data are analysed together with published information from Czechoslovakia. The mirid communities are very similar, containing 5 to 8 species feeding on cereals. The high dominance indices obtained (55.7-98.7) were due to Lygus rugulipennis Popp. The parasitization by braconids of L. rugulipennis on wheat averaged 0-13.6% in the study area in Finland, and 2.5-25% in Poland. The stableness of mirid communities and the mirid-braconid system in cereal ecosystems is dicussed.