Through a detailed study of the common methods of sorcery in Siquijor and their treatments, this thesis will try to show the extent to whcih the practice of sorcery and its closely related activities have so encroached into the practice of the Catholic faith to produce a form of folk religiosity now present in the place. At the same time, this research will provide information about the following matters which are directly related to the main topic: (1) the major methods of sorcery practiced in Siquijor; (2) the effects of sorcery on the way of life in general of the people; (3) the specific manifestations of sorcery, or its influences, on the people's practice of their faith; (4) the attitude of the Church and the course of action, if any, which the Church takes with regard to this situation; and (5) the pastoral approaches which can and should be adopted to bring Catholicism among the Siquijodnons to a more mature level.