The Diocese of Kazan (Russian: Казанская епархия, Tatar: Казан епархиясе) is an eparchy of the Russian Orthodox Church on the administrative boundaries of Kazan, Naberezhnye Chelny in the Republic of Tatarstan.

One way or another, missionary work in the Kazan region was rather sluggish, and the activities of the Kazan Theological Academy were reduced mainly to an in-depth study of the linguistic and cultural aspects of the existence of the peoples of the East.

At the beginning of the 19th century, the Kazan branch of the Bible Society was opened to translate the Holy Scriptures into local languages.

In 1847, a translation committee was opened at the Kazan Theological Academy, and in 1854 - three missionary departments.

To support missionary education, the Orthodox Brotherhood of St. Gurias was established on October 4, 1867.