This essay illustrates trucks and case studies related to the relationship between International Labour Organization and International Christian Unions. The essay is conceived as part of a wider publication, by Palgrave Macmillan, Social Justice & International Labor: The ILO- Roman Catholic Experience, 1919-1991, within the ILO Century Project to be celebrated in 2019. The sources used come from the ILO Archives and Secret Vatican Archives, entailing the international literature, both historical and juridical, on the subject. Beginning in the 1920's both the ILO and the Vatican reached out to Christian trade movement organizations in order to enlist them in the fight for standardized labor laws. With the Roman Catholic influence on labor and social justice moving forward in the 1930’s through the promulgation of various papal encyclicals, this emerging nexus seemed helpful to all parties. After World War II, the international trade union movement gained greater strength across Europe, while at the same time encountering new tensions with the Holy See. In the 1970’s the international Christian trade unions gained complete independence and are involved in the secularisation process, building up strict relationship with other trade union organisations, especially in the case of Italy and France. This essay looks at the emergence of those tensions, and their significance for the relationship of the Christian trade union organizations in the ILO
