Three teams qualified to enter the tournament alongside hosts Costa Rica, chosen to hold the tournament by UNCAF that same year. The teams played in a round-robin format, with the winner being the squad who obtained the best overall results. The first UNCAF Nations Cup match took place between El Salvador and Guatemala. Since the match ended in a 0-0 draw, the following one between Costa Rica and Honduras produced the first goal in UNCAF Nations Cup history. It was scored by Róger Gómez of Costa Rica. The mascot of the competition was a boy named "Minchito '91".
Hosts and pre-tournament favourites Costa Rica earned 6 points from three wins after defeating Guatemala 1–0 in front of a crowd of 16,500 people, and became the first nation to win the UNCAF Nations Cup.
During the Confederation of North, Central American and Caribbean Association Football (CONCACAF) Congress in Guatemala City, Guatemala on January 26, 1991, the qualification rounds for the inaugural CONCACAF Gold Cup was decided upon. Since Costa Rica were given a bye into the competition due to its first place standing at the 1989 CONCACAF Championship, which also served as a qualification phase for the FIFA World Cup hosted by Italy in 1990, they weren't required to participate in the preliminary stages. However, the final qualification round of the Central American zone had two bids: the United States and Costa Rica. Costa Rica won the bid and was named by CONCACAF and UNCAF as the host nation of the inaugural UNCAF Nations Cup tournament on February 19, 1991.
The draw for the 1991 UNCAF Nations Cup qualifying competition for Central America took place in Guatemala City on January 26, 1991. Six teams entered to compete for the three remaining places in the competition, alongside eventual host Costa Rica. The teams were divided into three groups of two. As the host nation of the event, Costa Rica qualified automatically. The qualifying process began in April 1991 and concluded in May 1991. At the conclusion of the qualifying group stage, the three group winners qualified for the tournament.
Minchito '91, the mascot for the 1991 competition, was the first UNCAF Nations Cup mascot, and one of the first mascots to be associated with a major sporting competition in Central America. Inspired in "the traditions, beliefs, legends and customs of Costa Rica", Minchito was born as an authentic peasant. The boy, who is seven-years-old, was created by the Hispanic Publicity Company. The name name is a diminutive of the name 'Benjamín' in Costa Rica. Minchito is dressed with a white shirt, a red scarf and belt with black shorts, the most common set of clothes of a Costa Rican peasant.
Each team's squad consisted of 18 players (two of whom must be goalkeepers). Teams also had two additional reserve players they could use as replacements in the event of serious injury, at any time. During a match, all remaining squad members not named in the starting team are available to be one of the three permitted substitutions (provided the player is not serving a suspension).