After having described the historical basis of the process of pillarization in Belgium, the author explains the emergence of the Catholic pillar as a defence mechanism of the Catholic Church and the Catholic leadership to protect the Catholic flock from sec- ularization. He describes the different services the Catholic pillar was offering for its members and the development of Belgium as a state based on three pillars: the catho- lic, the socialist and the liberal one that were all three institutionalized. This structure meant that Belgium was rather a segregated country that was vertically integrated. In the sixties of last century, the pillar was confronted with a growing secularization of the population, which forced the leadership of the pillar to adapt the collective con- sciousness: the Catholic credo, values and norms were replaced by so-called typical values of the Gospel integrated in what is called a Socio-Cultural Christianity. Under the impact of the changing economic situation, the politicization of the Flemish ques- tion and the emergence of Ecologist parties, the Christian pillar had to adapt its serv- ices and is now based on clienteles rather than members. Only in the Flemish part of Belgium is it still an institutionalized pillar.