 On 16 October 2010, Pope Benedict appointed Koch as a member of the Congregation for the Doctrine of the Faith for a five-year renewable term.On 20 October 2010, Pope Benedict XVI made him Cardinal-Deacon of Nostra Signora del Sacro Cuore.On 29 December 2010, Koch was appointed a member of the Congregation for the Oriental Churches and the Pontifical Council for Interreligious Dialogue.