Catechism in the pastoral ministry of St. Josaphat Kuncewicz Since the martyrdom of Archbishop Josaphat Kuncewicz have already passed 390 years and 90 years since the release of the encyclical of Pius XI “Ecclesiam Dei” issued on the occasion of 300th anniversary of the death of the saint. Josaphat Kuncewicz is known as a reformer of religious life in Ukraine and Belarus. He led in his archdiocese deep reformist activity, both administrative as pastoral, focused on raising the intellectual and moral level of the clergy. He also prepared Catechism, which can be categorized as small catechism. Due to its content and form it was a simple tool which allowed for synthetic learning of the basic truths of the faith and principles of Christian life. Originality of the Kuncewicz’s Catechism is to show the Eastern tradition in a catechism, which had the structure of the western tradition.