This paper not only clarifies the concepts of secularism and secularization, but also analyzes them, and in its final part it evaluates them. The phenomenon of secu-larism is defined as an ideological and active attitude of hostility toward everything that is Christian. In turn, secularism, quite strongly associated with the current form of culture of societies and their development, is seeking autonomy and freedom. Rad-ical (sometimes irresponsible) secularization thesis of the Protestant (R. Bultmann, K. Barth, D. Bonhoeffer, E. Fuchs, F. Gogarten, G. Vahanian, P. van Buren, W. Ham-ilton, Th . J. Alitzer, J.A.T. Robinson, D. Sölle, W. Pannenberg) mind has been adopted by most Catholic theologians with a reasonable reserve. Catholic doctrine accepts the autonomy of temporal realities and a specifically understood process of profanation of the world (constructio mundi and consecratio mundi). However, the fact that different sectors of earthly life are governed by their own relevant laws, does not mean that the created things are totally independent of God, or that man can dispose of them freely and without any relation to the Creator (K. Rahner, J. B. Metz, P. Teilhard de Chardin, M. D. Chenu, J. Danielou, G. Thils, Ch. Duquoc, J. Maritain, H. de Lubac, Y. Congar, Cz. Bartnik, A. Skowronek, A. Nossol, J. Mariański). The position of the Catholic Church on this matter is contained in the conciliar Constitution Gaudium et Spes.