Using authentic material from inhabitants of Lithuania Minor, the article analyses the specific nature of the feast of Pentecost in this region, in terms of its chronological development (starting with the first written references up to this day), in order to reveal the most conspicuous stages in its development, and modern transformations of the customs and traditions. The article covers the main elements of the feast of Pentecost for the Lietuvininkai dating from the end of the 19th and the 20th century. These elements are then compared to the feast of Pentecost in other regions, in order to reveal structural and functional changes in calendar festivals.