The division of the Finnish labour movement is studied in this article through the choice of Yrjö Mäkelin, one of the prominent members of the Finnish labour movement since its foundation. Yrjö Mäkelin made his choice in the beginning of 1922, when he was released from the prison where he had spent almost four years. During that time the Finnish labour movement had been divided, and Mäkelin had to ponder on which party to choose. Mäkelin’s earlier career, especially his wish to get the labour movement to work together with the bourgeois parties in order to achieve independence for Finland, would have suggested that he join the Social Democratic Party; but he decided to enter the ranks of the Socialist Workers’ Party which had contacts with the underground Communist Party. Although Mäkelin was not a very active participant in the abortive revolution and in the civil war in the winter and spring of 1918, it was an important factor in his decision. The stance of his family and the whole labour movement in the northern Finland also had an influence on Mäkelin’s choice. He, however, emphasised that he would join the Socialist Workers’ Party while following his own programme, which expressed doubts about the ideas of centralisation and strict discipline the communist movement had launched. He stayed within the party, although the leaders of the Communist Party wanted to expel him.