The former Catholic diocese of Maillezais in north-west France was erected in 1317, by Pope John XXII, and ceased to exist in 1648 when it was incorporated into the new diocese of La Rochelle. The town of Maillezais is now found in the department of Vendée, and most of the territory of the former diocese belongs to the diocese of Luçon.

The Diocese of La Rochelle and Saintes is a Latin Church diocese of the Catholic Church in France. The diocese comprises the département of Charente-Maritime and the French overseas collectivity of Saint-Pierre and Miquelon. The bishop is a suffragan of the Archbishop of Poitiers. The episcopal seat is in La Rochelle Cathedral. Saintes Cathedral is a co-cathedral.