Object of this study is the ecumenical mandate of the church as it can be derived from Jesus? biblical legathy in John?s Gospel (Jn 17, 21) and implemented in the church of today. In a first stepbesides the term "ecumenism" its biblical foundation, historical mile- stones and the intensification of ecumenical endeavors are pointed out. Based on the theology of the Second Vatican Council (1962-1965) with its decree "Unitatis redintegratio" on ecumenism, and after some comments on prerequisites of the Vatican Council the starting point, chief purpose and impact of the decree on ecumenism are analyzed. The major cognitional interest of this thesis is how the decree on ecumenism was implemented on the level of the local church with the diocese of Gurk as an example. A "Diocesan Commission for Ecumenical Issues" (with catholic members) and a "Commission for Ecumenical Contacts" (with members of various denominations) can be ranked among the important accomplishments on the diocesan level. In addition to that, there were numerous ecumenical initiatives in Carinthia, such as common worship services, events, workshops, days for parish priests, and worldwide prayer weeks for unity among Christians. In 1971 and 1972 the Diocesan Synod of Carinthia "Church for the World" took place; some of its decisions focused on "Ecumenical Collaboration". The responses to them and the medial echo of the ecumenical climate in Carinthia give witness to a lively and dynamic process of ecumenical development. The thesis ends with a summarizing overview and some personal and ecclesial statements which emphasize - as résumé - the desire to move forward towards the visible unity of Christ?s church. Even 50 years after the promulgation of the decree on ecumenism, ecumenism remains a mandate and a challenge to the church and still needs the support of all believers through dialogue and prayer for Christian unity.