Catedral Basílica de Mercedes-Luján

Catedral Basílica de Mercedes-Luján is the cathedral of the Roman Catholic Archdiocese of Mercedes-Luján and a minor basilica in Mercedes, Buenos Aires Province, Argentina. It is situated 100 kilometres west of the Federal Capital. It serves the Archdiocese of Mercedes-Luján and houses the Episcopal Chair. Built in 1904 in Gothic Revival style. It contains the remains of Don Saturnino Unzué and Doña Inés Unzué Dorrego, its main benefactors. On 15 April 2010, the building was declared a National Historic Landmark under Decree 492/2010.

This cathedral is dedicated to Our Lady of Mercy. It should not be confused with the Basilica of Our Lady of Luján, a much bigger and famous temple which is located in the same diocese.