In this work we have reconstructed the process of gestation and constitution of the General Union of Workers (UGT). This workers central has been relegated in historiographic studies. There are three objectives of this article. Firstly, we examine the reasons that led to the formation of the UGT, highlighting the importance of the newspaper La Organizacion in this process. Secondly, we establish that the UGT was not a worker central designed and controlled by the Socialist Party (PS), correcting a common misunderstanding. Thirdly, we point out the existence of a working-class and anti-political current within the workers' movement and its impact on the formation process of the UGT. To carry out this research, we have surveyed party, union, neighborhood and commercial sources. In addition, we accessed unpublished documents that have allowed us to delve into the main debates that took place at the founding congress of the UGT. With this work, we intend to contribute to the general knowledge of the working class of the period and contribute to the study of the UGT, an institution little known but key in the social struggles of the first decade of the 20th century. Finally, we suggest that the presence of this anti-political and workerist current, in the formation of the UGT, may explain the facilities that the revolutionary unionists had, those who quickly conquered the leadership of the workers' union.