[1] The diocese consists of fifteen towns in the province of Catania: Caltagirone, Castel di Judica, Grammichele, Mazzarrone, San Michele di Ganzaria, Raddusa, Ramacca, Mirabella Imbaccari, Scordia, Militello in Val di Catania, Palagonia, Mineo, Licodia Eubea, San Cono and Vizzini.

The main town, where is St. Julian's cathedral church, is Caltagirone.

The diocese was created on 12 September 1817 with the papal bull Romanus Pontifex of Pope Pius VII, and the permission of the King of Naples which was registered on 20 February 1818.

[2] Originally it was a suffragan of the diocese of Monreale, but from 20 May 1844 it entered in the ecclesiastic province of Siracusa.

From 2 December 2000, with the Pope John Paul II's papal bull, Ad maiori consulendum, the diocese became a suffragan of archdiocese of Catania.