The Diocese of La Rochelle and Saintes (Latin: Dioecesis Rupellensis et Santonensis; French: Diocèse de La Rochelle et Saintes) is a Latin Church diocese of the Catholic Church in France.

This diocese before the French Revolution, aside from Maillezais, included the present arrondissements of Marennes, Rochefort, La Rochelle, and a part of Saint-Jean-d'Angély.

St. Louis of France is the titular saint of the cathedral of La Rochelle and the patron of the city.

In 1627, however, the alliance of La Rochelle with the English proved to Louis XIII and to Richelieu that the political independence of the Protestants would be a menace to France; the famous siege of La Rochelle (5 August 1627 – 28 October 1628), in the course of which the population was reduced from 18,000 inhabitants to 5000, terminated with a capitulation which put an end to the political claims of the Calvinistic minority.

A seminary was established by royal order, with an income of 3000 livres, derived from an assessment on all of the benefices in the diocese.

The electors of Charente-Infeurieure assembled on 27 February 1791 and elected Isaac-Étienne Robinet, the curé of Saint-Savinien-du-Port as their Constitutional Bishop.

Bishop Robinet resigned on 6 December 1793, and took up residence with his brother at Torxé, where he died on 8 September 1797.