In the Philippines, in public elementary schools and high schools, at the discretion of their parents, children are allowed to be taught religion by instructors assigned by religious organizations. At present, several religious organizations, especially the Catholic Church, send their instructors to teach religion in public schools to those children who belong to their own religions for not rnore than 30 minuted three times a week. This practice has been followed since the start of the American regime, that is, since the beginning of this century. Describing frequent arguments over the practice and its modifications throughout this century, this paper demonstrates the following points. In the first place, the provision was modified immensely during the 1950s. Until that time, religious instruction was given only outside the regular school timetable, but in 1953 an Administrative Order issued by President Quirino permitted religious instruction to be given within the school timetable as well as outside it. The new provision was reiterated in the Education Order of 1955. This modification resulted in increasing popularity of the practice, a state of affairs which has continued up to the present. In the second place, as an issue of educational policy, religious instruction was so critical that the argument influenced personnel matters within the Department of Education and presidential election results in the 1950s. In 1953, the Catholic Church loudly accused the Secretary of Education and two other officials of having neglected the implementation of religious instruction. Later in the presidential election of that year, the Church supported candidate Magsaysay, who promised the Church that he would appoint as Secretary of Education a man representing the sentiments of Catholics. And in 1955, in opposition to the drastic change in policy, a petition was filed with the Supreme Court to test the validity of the Education Order. In the third place, the Catholic Church played an important role in the development of the practice. In its need to expand religious education and provide more opportunities to teach the Catechism, the Catholic Church insisted on liberalizing the provision. Since the Church had an influence on the result of elections, pressure from it drastically changed the policy of Congress and Presidents on religious instruction. In the fourth place, the demand for religious education has been strong among the Filipino people, most of whom are devout Catholics. The demand was so strong that at the beginning of this century many people did not send their children to newly established public elementary schools where the Catechism was not taught. This demand was especially strong in the early 1950s because of the problem of juvenile delinquency and the threat of the arm of the Communist party named "Hukbalahap".