The paper explores various issues of dechristianization as the factor which affects negatively on the institutions of capitalism. The point is that market capitalism cannot function effectively without adequate work of the forward contracts' system. In turn, this system can normally function only under special informal institutions and features of human behavior. These ones are mainly low degree of opportunism, high propensity to undertake, high propensity to fulfill commitments, high degree of mutual trust, and absence of investor myopia. The most of these features had been shaped - in the Western countries - by the Christian ethics. The process of dechristianization in the Western countries (especially in the Western Europe) - which has been analyzed and showed in the paper - destroys both these norms and institutional foundations of capitalism. The consequence is both the fall of economic efficiency and rising susceptibility of contemporary capitalism to deep recessions.