Kommission für Glauben und Kirchenverfassung
Vischer's tenure with the World Council of Churches began in 1961 with his appointment as research secretary on the council's Commission on Faith and Order. From 1962 to 1965, he was a WCC observer at the Second Vatican Council. He was director of the Faith and Order Commission from 1966 to 1979, then director of the Protestant Office for Ecumenicism in Bern. He was moderator of the theological department of the World Alliance of Reformed Churches from 1982 to 1989.