You can exchange currency or traveler's checks at almost any bank in Guatemala City. Banquetzal is one of many banks with numerous branches around town, including one at the airport. Baco Agromercantil has a large office on Avenida La Reforma between Zonas 9 and 10. Bancared is Guatemala City's largest network of ATMs with 150 outlets around the city, as well as about 80 around the rest of Guatemala. Several upscale hotels have ATMs on the premises.
Banco Agro Mercantil (Av. La Reforma, Zona 9. 2331-1501) Banquetzal (Aeropuerto Internacional La Aurora, Zona 13. 2362-9741)