Club Atlético Osasuna is one of only four clubs in Spanish football - alongside Real Madrid, FC Barcelona and Athletic Bilbao - that remains owned by its members (socios) and is run by an elected president rather than a corporate structure. The club was founded on 24 October 1920 in Pamplona as a continuation of the Sportiva Foot-Ball Club, active since 1919; its name, meaning "health" in Basque (in the sense of strength or vigour), was given by Benjamín Andoain Martínez. The club adopted its current form, Club Atlético Osasuna, in 1926.
The team plays in red shirts and navy blue shorts, and together with its nicknames "Los Rojillos" and the Basque "Gorritxoak" (both roughly meaning "The Little Reds") this sets it apart from other clubs in the region. Osasuna play their home matches at the Estadio El Sadar, known for its exceptionally loud and loyal crowd, widely regarded as one of the team's assets on home soil.
Osasuna have never won the Spanish league title or a national cup, but they have twice reached the Copa del Rey final. The first, played in 2005 against Real Betis, is remembered as one of the most dramatic finals of recent decades - Betis only won it in extra time after a level score in normal play. The second final, in 2023, was lost to Real Madrid. The club's best-ever league finish is fourth place in La Liga, achieved in the 1990-91 and 2005-06 seasons - the latter earning entry into Champions League qualifying, though the team ultimately continued its European campaign in the UEFA Cup.
Today, Osasuna remain firmly established in La Liga and stand as a symbol of Navarre - a club that, despite lacking major trophies, has built a strong identity rooted in fan loyalty and its members-owned model.