The occurrence of parasites in wild boars in the Olsztyn province has been analysed. It was found that trichinellosis in the period from 1975 to 1990 occurred in 191 animals (0.229%), lung worms in 6442 (7.72%), hadatidosis in 3463 (4.5%), cysticercosis in 12 (0.014%) and liver fluke in 7 (0.008%). There was observed a distinet increase of T. spiralis extensiveness. A marked number of trichinellosis was noted especially in 1985 and 1990 (0.421% and 0.452% respectively). Liver fluke and cysticercosis appeared only three times: liver fluke in 1979, 1988 and 1990 (extensiveness from 0.02% to 0.05%) and cysticercosis in 1978, 1987 and 1990 (from 0.02% to 0.14%). Hadatidosis and roundworms were found every year: extensiveness of hadatidosis fluctuated from 4.15% to 7.72% and roundworms from 4.24% to 12.82%.