In this work the author gives a survey of the development of certain segments of Catholic social teaching concerning problems of war and peace. After a lengthy historical review, special attention is ...given to the contribution of the Second Vatican Council to the topic in question, and especially to the "substitution" of the theory of a just war with the theory of avoiding war. Accordingly, the key messages of Pope John XXIII, Paul VI and John Paul II regarding issues of war and peace in the contemporary world are presented. They have considerably contributed to the actualization of the Catholic social teaching because they "coordinated" the teaching of the Church with the current events in the contemporary world. Namely, the concepts of war and peace are no longer unambiguous, but are linked to the pressing issues of justice, solidarity and development on a global level. In the second part of the article the author discusses specific messages of representatives of the Catholic Church in Croatia dedicated to wartime events.