Diplomová práce se zabývá řeholní kongregací Salesiánů Dona Boska, jejich aktivitami a preventivním výchovným systémem, jenž je primárně realizován v salesiánských střediscích mládeže a poukazuje i na stavební činnost salesiánů, která je neodmyslitelně spojena s jejich dílem.The main part of my thesis deals with two topics. The first one concerns the establishment, development and contemporary activities of Salesian youth centres in Moravia, the second one concentrates on Salesian bulding activities. The Salesians have been active in the Czech Republic for over eighty years. The first Salesian centre was built in the Moravian town of Fryšták. It was managed by the first Czech Salesian P. Ignác Stuchlý. During the Second World War and the period of communist dictatorship, the Salesian work went through a lot of changes. Their activities, including building works, were very limited. Salesian youth centres are the priority of Salesian work in the Czech Republic. In all the centres Salesian way of education based on sense, kindness and faith is applied. The oldest church of the three churches described above is St. Joseph in Ostrava. It was built between 1936 and 1937 in functionalist style. It has a special steel construction which is fitted to an armoured concrete grid. At that time this buiding was unique. Churches of Our Lady Help of Christians in Brno-Žabovřesky and in Zlín-Jižní Svahy are similar in many respects. Both are modern structures built after 1990 according to the needs for modern church architecture. They are beautiful, practical, built from quality materials and naturally fit in the places of housing estates.