The club was founded in 1928 as Germania; after ten years of existence, their name would be changed to ADIX(Asociación Deportiva Independiente de Xelajú), and during that time the uniform colors were established as red jersey and blue shorts, a combination that remains to date. The team was renamed Xelajú Mario Camposeco in honor of local footballer Mario Camposeco who was the captain of the club in the 1940s, helped them win 10 consecutive Quetzaltenango department titles, and who was still an active player when he died in a plane crash in 1951.
The Superchivos have been Guatemalan champions five times, first in 1961/62, again in 1980, a third time in 1995/96, a fourth time in the 2006/07 season, and a fifth in 2011/2012. Xelajú has won the Copa Centenario once, in 1972/73. In the 2007 Clausura tournament, they eliminated five-time defending champion Municipal in semifinals, to reach their first final since the inception of the Apertura/Clausura format. They faced Deportivo Marquense, losing the first match 0-1 and winning the second match 4-1, for a global score of 4-2 which gave them their fourth championship. It was the first time since 1980 that two teams from outside of Guatemala City finished first and runner-up.