Libertador Building, Military headquarters in Buenos Aires, Argentina.

The Libertador Building is a government complex on Azopardo Street 250 in Monserrat, Buenos Aires, with a 230-metre facade divided into two wings joined by a central section with two inner courtyards. Its French Renaissance design includes an imported slate mansard roof over the top three floors and facades clad in faux stone of white cement, marble and limestone sand. It has a double-height ground floor and 16 upper floors, and houses the Ministry of Defense, the Army General Staff and the Joint Chiefs of Staff.

The War Ministry was planned from 1935, when Carlos Pibernat of the General Engineers' Office drew up the design under President Agustín Justo; construction began in 1938 on a 3-hectare lot east of the Casa Rosada. It replaced the ministry's old home in a former National Mint building in Montserrat. The building was inaugurated in April 1943 by President Ramón Castillo, and in 1950 Juan Perón renamed it Edificio Libertador for the centenary of José de San Martín's death.

The building was renamed Edificio Libertador in 1950, the centenary of General José de San Martín's death, when President Juan Domingo Perón declared that year the Year of the Liberator General San Martín. Inside, the Salón San Martín has marble floors and walls, a tall ceiling and a symmetric classical layout.

The building occupies a 3-hectare lot on Azopardo Street 250, east of the Casa Rosada in the Monserrat neighbourhood, not on Avenida Colón. It is an active Ministry of Defense and Army headquarters, so access is restricted; the 230-metre façade can be viewed from the public street.

The building's 230-metre facade is split into two wings joined by a central section set further forward, which has four more floors than the wings and its own portico. The Hall of San Martín inside has marble floors and walls.