Club Atlético Nacional, best known as Atlético Nacional, or simply Nacional, is a Colombian professional football club based in Medellín. The club is one of only three clubs to have played in every first division tournament in the country's history, the other two being Millonarios and Santa Fe.

Atlético Nacional was founded in 1947 as Club Atlético Municipal de Medellín by Luis Alberto Villegas López, a former president of the football league of Antioquia. The team adopted its current name in 1950. The current owner, Organización Ardila Lülle, officially acquired the team in 1996. According to CONMEBOL, Atlético Nacional is the club with the largest fan following in Colombia, with more than 15 million fans.

Atlético Nacional plays its home games at the Atanasio Girardot stadium, which has a capacity of 40,043. They share the stadium with their local rivals, Independiente Medellín. The teams face each other in a local derby known as El Clásico Paisa, which is considered one of the most important local derbies in the country. Atlético Nacional also has rivalries with Millonarios and América de Cali, two of the most important rivalries in Colombian football and South America.

Considered to be one of the strongest clubs from Colombia, it is one of the most consistent clubs in the country. Nacional is the only Colombian club that has won the two domestic short-format tournaments in a single year, Apertura and Finalización, since the format was established in 2002, winning the titles of the 2007 and 2013 seasons. The club has won 18 league championships, eight Copa Colombia and four Superliga Colombiana titles, for a total of 30 domestic titles, making it the most successful team within Colombia. It was also the first Colombian club to win the Copa Libertadores in 1989 and, after winning the title again in 2016, the most successful Colombian side in that tournament. It also has the most international titles of any Colombian club, having also won the Copa Merconorte twice, the Copa Interamericana twice, and the Recopa Sudamericana once, for a total of seven international trophies and 37 overall.

In 2016, Atlético Nacional was ranked by IFFHS as the best football club in the world, becoming the first South American club, and the first outside Europe, to receive such an honor in that ranking. It ranks 58th in the world ranking of the best clubs of all time according to the IFFHS, being the second-best-ranked Colombian team on the list. It is also ranked as the second-best Colombian club of the 20th century and as the best Colombian club so far in the 21st century. Nacional is also credited as the best Colombian team in CONMEBOL club tournaments and ranks 17th in the official club ranking of the Copa Libertadores.

As of 1 January 2021, Atlético Nacional had 9.39 million followers on social media, making it the most-followed club in Colombia and one of the most-followed clubs in South America.

History Atlético Nacional was founded as Club Atlético Municipal de Medellín on 7 March 1947 by a partnership led by Luis Alberto Villegas López, former president of the football league of Antioquia. The club was created to promote sports in the city, especially football and basketball. It was based on Unión Indulana Foot-Ball Club, an amateur club from the Liga Antioqueña de Fútbol, the local amateur football league. Officially, the founding members were: Luis Alberto Villegas Lopera, Jorge Osorio, Alberto Eastman, Jaime Restrepo, Gilberto Molina, Raúl Zapata Lotero, Jorge Gómez Jaramillo, Arturo Torres Posada and Julio Ortiz.

Atlético Nacional joined the professional league for its first edition in 1948. For that tournament, each club had to pay a fee of 1,000 pesos (at that time, approximately US$1,050). Atlético Nacional played the first match of the history of the tournament, a 2–0 victory over Universidad. The tournament had ten participants that season and Atlético Nacional was 6th with seven victories, four draws and seven defeats.

Atlético Municipal changed to its current name, Atlético Nacional, for the 1951 season.Ruíz Bonilla, Guillermo (2008). La gran historia del Fútbol Profesional Colombiano. Ediciones Dayscript. pp. 12–14, 19. . The name change was made as a way to reflect the main philosophy of the club: to encourage the national sportsmanship. That philosophy was also reflected in the club's policy of signing only national players, which held special meaning during Colombia's El Dorado period, a time when most Colombian clubs were aggressively pursuing foreigners. It was not until 1953 that the club signed their first foreign player, Argentine Atilio Miotti.

Atlético Nacional won its first league title in 1954. Manager Fernando Paternoster (who managed the team from 1948 to 1951 and from 1954 to 1957) guided the team through a season in which they lost just once (to Boca Juniors de Cali). The star was Argentine striker Carlos Gambina, who led the league with 21 goals.

Economic troubles plagued the team in the late 1950s, and during 1958 the club was briefly forced to merge with crosstown rivals Independiente Medellín. These financial problems and occasional returns to the club's policy of only signing Colombian players hampered results, and the club failed to win another title for nineteen years.

The drought was finally broken in 1973. The revival had actually started after the 1970 season, with the hiring of manager José Curti and the signing of midfielder Jorge Hugo Fernández. In 1971, Nacional won the Apertura title and only narrowly lost the national championship to Santa Fe (they fell 3–2 in a second replay of a bitterly fought championship playoff). Following a strong finish in 1972, Nacional won its second league title in 1973. They qualified for the final stage by winning the Torneo Finalización with 34 points, then finished first in a three-way round robin against Millonarios and Deportivo Cali. This championship was followed up by a runner-up finish in 1974.

1976 saw a new era for the club begin, with the hiring of Argentine manager Osvaldo Zubeldia. With his strong emphasis on conditioning and physical play, Zubeldia was able to manage the club to two further titles, 1976 and 1981, as well as regular finishes towards the top of the table. During the Zubeldia era, the heart of the team was César Cueto, central midfielder and team captain from 1979 to 1983. During the 1981 championship season, Cueto was voted the league's player of the year. This successful era ended with Zubeldia's sudden death of a heart attack in January 1982. Nacional remained a power in Colombia, but the death of their manager, the departure of Cueto, and the rise of América de Cali (the Red Devils won five straight championships in the 1980s) left its fans dissatisfied, and began a decade-long trophy drought.

Determined to break their stranglehold, the club made a significant change in 1987. First, they appointed Francisco Maturana as manager. A regular in the team's defense during the 1970s, Maturana was considered a rising star in Colombian football management and had just been named manager of the national team. Maturana was thus simultaneously trying to lead the club to a domestic title and assemble a national side that could qualify for the World Cup. The two goals were complementary; Atlético Nacional's traditional preference for Colombians over foreigners made them a natural base for Maturana to build his national team upon. However, there was also another development of more questionable legality; in the 1980s, Nacional was linked to the Medellín Cartel. Its leader, Pablo Escobar, who was also the most prominent of Colombia's drug lords, was a fan of both football and betting, and also wanted to invest in a local club and find a way to launder his drug money. Although Escobar never took a public role, the money he poured into the club made a major impact. In Maturana's words, "The introduction of drug money into soccer allowed us to bring in great foreign players. It also kept our best players from leaving. Our level of play took off. People saw our situation and said Pablo was involved. But they couldn't prove it".

Regardless of how the club was assembled, by 1987 they had a strong roster featuring a collection of Colombian internationals. In goal was René Higuita, a keeper known for his tendency to leave his area. In defense they had Andrés Escobar and veteran Luis Fernando Herrera. The midfield featured Leonel Álvarez (capped over 100 times for Colombia) and Alexis García (team captain and Medellín native). In the attack, the club could count on John Jairo Tréllez, one of the country's most prolific goal-scorers. This lineup was good enough to finish second in both the Apertura and Finalización, qualifying for the championship round, in which they finished fourth.

The 1988 season was even better, as the club qualified for the championship round again, finishing as runners-up behind Millonarios. That result was good enough to qualify the team for the 1989 Copa Libertadores. The entire focus of the 1989 campaign was on the Copa Libertadores, which Atlético Nacional hoped to become the first Colombian club to win the competition. In the group stage, Los Verdolagas were placed with fellow Colombian side Millonarios, as well as Ecuadorian clubs Deportivo Quito and Emelec. Two wins and three draws allowed Nacional to advance out of the group stages for the first time in five attempts. In the round of 16, they defeated Racing Club of Argentina by an aggregate score of 3–2. That sent them into the quarterfinals for an all-Colombian matchup with Millonarios, their group stage opponent. Nacional won the first leg 1–0, then held out for a 1–1 draw in a controversial match in Bogotá, advancing to the semifinals. In the semifinals the team faced Danubio of Uruguay. The away match ended in a 0–0 draw, but four goals from Albeiro Usuriaga sparked a 6–0 rout in the return match to send the club into the finals. In the finals, they faced Paraguay's Olimpia, who had already played two Libertadores finals in their history. The first leg, played in Asunción, saw Olimpia grab a 2–0 win. Nacional answered in the second leg (played in Bogotá on the grounds that the Estadio Atanasio Girardot in Medellín was too small) with a 2–0 win of their own. The tie went into penalty kicks, where Nacional won 5–4, giving the club its first Copa Libertadores title, while becoming the first Colombian club to win the competition as well.

Whilst the club hit that milestone abroad, the domestic league season was cancelled due to the assassination of referee Álvaro Ortega on 1 October after a match between Independiente Medellin and America de Cali. Although Pablo Escobar did not murder the referee himself, it is believed that one of Escobar's hitmen did. Later that month, the team played the Supercopa Libertadores and were eliminated in the quarterfinals by Independiente.

On 17 December, Nacional played the 1989 Intercontinental Cup against Milan, champion of the 1988–89 European Cup. The result was a 1–0 defeat with a 119-minute free kick goal from Alberigo Evani. As champion of the Copa Libertadores, Nacional also played the 1989 Copa Interamericana against Pumas UNAM, winner of the 1989 CONCACAF Champions' Cup. It was played over two legs, and Nacional won it with an aggregate score of 6–1. They also played the 1990 Recopa Sudamericana against Boca Juniors, which finished in a 1–0 defeat.