General characteristic of parasitologic situation at the exclusion zone, some aspects of new conditions influence on separate systematic groups of mammal parasites Polesye State Radiation and Nature Reserve of the Republic of Belarus were presented. Research of helminth fauna and helminthological situation was realized by an example of 1 European bison, 7 mooses, 20 roe deers, 26 boars, 25 wolves, 50 racoon dogs, 6 foxes and 3 beavers. Scatoscopy of the animal excrements was realized by Kalantaryan method with saturated solution of sodium saltpeter, Berman method. Research results revealed 66 helminth species belonging to 4 classes and 34 families. There were found 10 parasite species at bison, 16 – at mosses, 17 – at roe deers, 16 – at boars, 8 – at deers, 23 – at wolves, 13 – at raccoon dogs, 13 – at foxes, 9 – at badgers and 1 – at beavers. Analyze of helminthofauna of the analyzed area showed that the nature reserve had its own helminthes complex. A lot of stated helminth species were parasites with a wide range of hosts, including domestic animals, and cattle. Wolves, foxes and raccoon dogs were hosts of some custodies invasions. Carnivorous animals and murine rodents were hosts of trichinosis invasion, which was stated at 41,2 % of raccoon dogs, 33,3 % of foxes and 16,7 % of wolves. Also trichinas were stated at bank vole (1,3%), yellow-necked mouse (2,7%), and house mouse (16,6%)