Annunciation Cathedral, Voronezh in the context of "Voronezh"

Christianity in Russia is the most widely professed religion in the country. The largest tradition is the Russian Orthodox Church. According to official sources, there are 170 eparchies of the Russian Orthodox Church, 145 of which are grouped in metropolitanates. There are from 500,000 to one million Old Believers, who represent an older form of Russian Orthodox Christianity, and who separated from the Orthodox Church in the 17th century as a protest against Patriarch Nikon's church reforms.

The Catholic Church estimates that there are from 600,000 to 1.5 million Catholics in the country, exceeding government estimates of about 140,000. There is one Catholic Archdiocese, Mother of God at Moscow, with three suffragan dioceses (Saint Clement at Saratov, Saint Joseph at Irkutsk, Transfiguration at Novosibirsk) and the Apostolic Prefecture of Yuzhno-Sakhalinsk. According to the Slavic Center for Law and Justice, Protestants make up the second or third largest group of Christians in Russia, with approximately 3,500 organizations and more than 1 million followers. A large number of missionaries operating in the country are from Protestant denominations.