["Journal for the Scientific Study of Religion, Volume 61, Issue 2, Page 433-449, June 2022. ", "\nAbstract\nThe operation of a religious organization under an oppressive regime, such as in communist countries, differs from that in a free society. There is extensive literature on the effects of regulation on competition in religious markets and on the religiosity of a population. Less attention has been given to the effects of oppressive regulation that aims to control and possibly eliminate religion rather than to promote a particular religious group. This paper focuses on the specific question of how churches deal with oppressive regulation, particularly how they choose between legal and illegal operation. It proposes that both the official and the black‐market way of supplying religious services have some advantages and disadvantages, and that dual operation is advantageous where the regulation is severe. The paper examines the operation of the Catholic Church in Central European countries under communist rule, particularly Czechoslovakia, Poland, Hungary, and Ukraine, and the different strategies adopted by the Church concerning official and underground operation.\n"]