John Paul II named him Prefect of the Congregation for the Doctrine of the Faith and President of the Pontifical Biblical Commission and of the International Theological Commission on 25 November 1981. On 15 February 1982 he resigned the pastoral governance of the Archdiocese of Munich and Freising. The Holy Father elevated him to the Order of Bishops assigning to him the Suburbicarian See of Velletri-Segni on 5 April 1993.
He was President of the Preparatory Commission for the Catechism of the Catholic Church, which after six years of work (1986-1992) presented the new Catechism to the Holy Father.
On 6 November 1998 the Holy Father approved the election of Cardinal Ratzinger as Vice-Dean of the College of Cardinals, submitted by the Cardinals of the Order of Bishops. On 30 November 2002 he approved his election as Dean; together with this office he was entrusted with the Suburbicarian See of Ostia.
In 1999 he was Special Papal Envoy for the Celebration of the XII Centenary of the foundation of the Diocese of Paderborn, Germany which took place on 3 January.
Since 13 November 2000 he has been an Honorary Academic of the Pontifical Academy of Sciences.
In the Roman Curia he has been a member of the Council of the Secretariat of State for Relations with States; of the Congregations for the Oriental Churches, for Divine Worship and the Discipline of the Sacraments, for Bishops, for the Evangelization of Peoples, for Catholic Education, for Clergy and for the Causes of the Saints; of the Pontifical Councils for Promoting Christian Unity, and for Culture; of the Supreme Tribunal of the Apostolic Signatura, and of the Pontifical Commissions for Latin America, "Ecclesia Dei", for the Authentic Interpretation of the Code of Canon Law, and for the Revision of the Code of Canon Law of the Oriental Churches.
Among his many publications special mention should be made of his "Introduction to Christianity", a compilation of University lectures on the Apostolic Creed published in 1968; "Dogma and Preaching" (1973) an anthology of essays, sermons and reflections dedicated to pastoral arguments.
His address to the Catholic Academy of Bavaria on "Why I am still in the Church" had a wide resonance; in it he stated with his usual clarity: "one can only be a Christian in the Church, not beside the Church".
His many publications are spread out over a number of years and constitute a point of reference for many people specially for those interested in entering deeper into the study of theology. In 1985 he published his interview-book on the situation of the faith (The Ratzinger Report) and in 1996 "Salt of the Earth". On the occasion of his 70th birthday the volume "At the School of Truth" was published, containing articles by several authors on different aspects of his personality and production.
He has received numerous "Honoris Causa" Doctorates, in 1984 from the College of St. Thomas in St. Paul, Minnesota; in 1986 from the Catholic University of Lima; in 1987 from the Catholic University of Eichstätt; in 1988 from the Catholic University of Lublin; in 1998 from the University of Navarre; in 1999 from the LUMSA (Libera Università Maria Santissima Assunta) of Rome and in 2000 from the Faculty of Theology of the University of Wrocław in Poland.
On Tuesday 19 April 2005, the College of Cardinals elected Cardinal Ratzinger as successor to Pope John Paul II - the 265th Bishop of Rome and Successor of St Peter.