Roberto Duran held world titles at four different weights - lightweight (1972-79), welterweight (1980), junior middleweight (1983-84) and middleweight (1989) and was the second boxer to have fought in five different decades.

Born in Panamá to a Mexican father and a Panamanian mother, he had his first professional fight in 1967. After an initial adjustment he won thirty in a row, culminating in his first title bout in June 1972, where he controversially defeated Ken Buchanan at New York's Madison Square Garden for the WBA world lightweight championship. Duran knocked down Buchanan in the first round and dominated him throughout the fight. Duran followed up on his title winning performance with several non-title matches. Later that year, in another non-title bout, he lost a ten round decision to Esteban De Jesus. Duran got back on track with successful title defences against Jimmy Robertson, Hector Thompson, and former lightweight champion Guts Ishimatsu. In 1974, Duran would avenge his loss to De Jesus with a brutal eleventh round knockout. Overall Duran made twelve successful defences of his title (eleven coming by knock out), his last defence coming in 1978 where Duran fought a third fight with De Jesus, a unification match where Duran once again knocked out De Jesus and captured his WBC lightweight belt. Duran would give up the unified lightweight title in February 1979.

Vacating the lightweight title was a build up for an attempt at the welterweight title. Duran earned a pair of wins against former WBC welterweight champion Carlos Palomino and Zeferino Gonzales, setting the stage for a title bout against then undefeated WBC Welterweight Champion Sugar Ray Leonard. The venue chosen would be the Olympic Stadium in Montreal, the same location where Leonard won an Olympic gold medal during the 1976 Summer Olympics. On June 20, 1980, Duran captured the WBC welterweight title by defeating Leonard via a 15-round unanimous decision. The fight would become known as "The Brawl in Montreal". In the November re-match, however, Duran shockingly quit. Leonard has said that his strategy was to use speed and agility to taunt and frustrate Duran, believing it was his best chance of winning the fight. In round 8, Duran turned around, walked to his corner and gave up, supposedly saying the now famous words, "no más" (no more). However he claims to have actually said, "No quiero pelear con el payaso." (Meaning "I do not want to fight with this clown.") Another version of events has him saying, in Spanish, "I can't continue". Referee Octavio Meyran, perhaps as incredulous as was the rest of the world at what he was seeing, asked Duran if he was sure, and Duran then said, "No más, no más" (no more, no more). In violation of what any professional fighter does on the day of a fight, Duran gorged himself after the weigh-in, claimed he quit because he was having stomach cramps. The controversy regarding this bout continues to this day.

He took some time to recover from that fight, gaining even more weight to contend for the WBC world junior middleweight title, but losing in his first attempt at a championship in that division on the January 30 of 1982, against Wilfredo Benitez by a 15 round unanimous decision. Duran was also to lose his comeback fight in December 1982 in Detroit. Kirkland Laing, from London, shocked the boxing world, producing the type of display his talents promised yet he so rarely produced, taking the split decision. After being relegated to a 10 round walk out win over Englishman Jimmy Batten at The Battle of The Champions in Miami, Duran signed with promoter Bob Arum. This marked the beginning of a comeback in which he beat former world champion and now hall of famer Pipino Cuevas via a fourth round knock-out, which earned him a second crack at the junior middleweight title, this time against WBA champion Davey Moore.

The WBA title bout took place at Madison Square Garden on June 16, 1983, which also happened to be Duran's 32nd birthday. The result turned out to be a one sided affair as Duran dominated Moore throughout the bout. The pro-Duran crowd at ringside cheered as Duran relentlessly punished Moore. By the end of the sixth round, Moore's eye had swollen shut and he was floored near the end of the seventh. Finally the fight was stopped in the eighth round as Moore was taking such a horrific beating and Duran won his third world title. After the victory, Duran was hoisted up in the air as the crowd sang "Happy Birthday" to a sobbing Duran.

Duran later fought for the World middleweight title, meeting Marvin Hagler in Las Vegas in November 1983, but losing in a competitive fight that went the full fifteen rounds. Despite the loss, Duran was the first fighter to go the full distance with the great middleweight champion in one of his defenses. In June 1984, Duran was stripped of his junior middleweight title when the WBA did not approve of his fight with WBC world champion Thomas "Hitman" Hearns, and took away recognition of Duran as world champion the moment Duran stepped into the ring to box Hearns. Duran lost the fight after a vicious second round knock-out by Hearns.

Duran did not contend another title fight until 1989, but made the shot count when he won the WBC middleweight title from Iran Barkley in February, a fight in which Duran used Don Longanecker as a training partner. The fight is considered one of Duran's greatest achievements, as the 38 year old former lightweight champion took the middleweight crown, his fourth title. In a tough, back and forth fight, Duran knocked Barkley down in the eleventh round and won a close decision. The bout was named the 1989 "Fight of the Year" by Ring Magazine. His reign was short lived once again as Duran moved up to super middleweight for a third clash with Sugar Ray Leonard in December (a fight dubbed Uno Más--One More--by promoters), but lost in a decision. Duran seemed to be in decline after the fight, he attempted to win further middleweight titles in 1994, 1995 and 1996 (fighting for the minor IBC belt). In 1998, at the age of 47, he challenged 28 year old WBA middleweight champion William Joppy. Joppy, a trim, quick-fisted fighter, battered Duran to defeat in just 3 rounds. It was Duran's most emphatic loss since the Hearns fight, over a decade earlier. Duran then announced his retirement in August 1998, but was back fighting in 1999. In June 2000 he won a minor super middleweight title from Pat Lawlor but quickly lost it to Héctor Camacho.

After splitting fights with Jorge Castro and losing a rematch to Camacho, Duran went to Argentina to promote a Salsa music CD that he had just released. While there, he was involved in a dramatic car crash and required life-saving surgery. After that, he announced his retirement from boxing.

Duran's five world title belts, which he won in four different divisions, were stolen from his house in Panama in 1993 during a robbery allegedly staged by his brother-in-law, who gave them to memorabilia seller Luis González Báez, who will stand trial for trying to sell stolen goods. González Báez allegedly sold the belts to undercover FBI agents. He alleges that Duran authorized the sale of the five belts to him during a time that Duran was facing financial trouble. On September 23, 2003, a federal judge in Florida ordered the five belts returned to Duran.

His 70 wins by knockout place him in an exclusive group of boxers who have won 50 or more fights by knockout.

He finally retired in January 2002 with a professional record of 119 fights, 103 wins with 70 Kos. On October 14, 2006 Roberto was inducted into the World Boxing Hall of Fame in Riverside, California, and on June 10, 2007 into the International Boxing Hall of Fame in Canastota, New York.