The construction of the Agua Negra tunnel under the Andes Mountains between Argentina and Chile gives the scientific community a unique opportunity to build ANDES (Agua Negra Deep Experiment Site): an Underground Laboratory inside the tunnel at its deepest point. This site will be 1750 m deep under the Earth surface, and it will be the first of its kind in the Southern Hemisphere. The planning of ANDES is expected to be finished by mid 2011, before the excavation of the tunnel begins. The completion of the Agua Negra tunnel and the underground lab ANDES is expected to be in 2018.

The Fourth International Workshop for the Design of the ANDES Underground Laboratory follows the workshops held in April 2011 (Argentina), June 2011 (Brazil) and October 2011 (Mexico), and it is a call to the Particle and Astroparticle Physics community, specially the community in Latin America, to participate in the future planning and use of this international facility.