The diocese was established on 18 October 1925 as Diócesis de Santa Cruz de Rancagua, by Pope Pius XII by means of the papal bull Apostolici muneris ratio.

The diocese is headed by Guillermo Patricio Vera Soto, who was named Bishop by Pope Francis on 8 June 2021.

The diocese comprises the three provinces of the O'Higgins Region of Chile: Cachapoal, Colchagua and Cardenal Caro, with the exception of the comuna of Navidad, of the latter province, which belongs to the diocese of Melipilla.

This figure represents about 625,000 Catholics out of a total population of 781,000 persons.

This article on a Roman Catholic diocese in Chile is a stub.