The process of the protestant spreadig in Belarus in the post-war period was caused by some reasons. First, weakining of the Orthodox church influence on tne territories occupied by the German army. Second, knowledge of protestant denominations during people migration caused by World War I. Third, joining of the Western Belarus territories to Poland. On these territories, protestantism was most widely spread in Polesskoye woevodstwo. The main factors of the most dynamic spreading of protestantism in this woevodstwo, compared with other Western Belarus ones, were both missionery activity of neighbouring Ukrainian communities and influence of Polish protestant ones. The process of active growth of protestant denominations in Polesskoye woevodstwo took place in 1921- 1939. Alongside with already existing baptist evangelist communities new protestant denominations, such as pentecostals, adwentists, darbist spread and grew. Communities of pentecostals had more dynamic widespread among these denominations. But the policy of state authorities, aimed at restraining the protestant movement, restricted possibilities of its rapid spread.