The article concerns the organisation and religious activity of Jehovah’s Witnesses in Warmia and Masuria after World War II, to their suppression by the state in July 1950. The appearance of Jehovah’s Witnesses in these areas resulted from two natural and forced settlement processes. This community consisted of three groups of followers: Polish settlers, Ukrainians from the “Wisła” deportation action, and local groups cooperating with each other. In total, they formed a group of over a thousand people. From 1947, they were subject to the actions and repressive measures of the state and security authorities as the “American denomination.” They often also met with hostility from provincial communities, Catholic clergy and associations of Protestant Churches