Boxing has produced many champions with long winning streaks, but very few retire without a loss. The two most famous undefeated fighters in the sport are Rocky Marciano and Floyd Mayweather Jr., whose all-time records continue to be used as benchmarks whenever another fighter begins to reach his undefeated streak.
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Marciano retired in September 1955 with a record of 49-0 (43 KOs) after defeating Archie Moore to retain the heavyweight championship. His mark became one of boxing’s most revered records and stood for decades as an undefeated career standard at the top level.
Mayweather later surpassed that number, finishing his professional career 50-0 (27 KOs) following his victory over Conor McGregor in August 2017. Two years earlier, Mayweather had already hit one of the sport’s most lucrative milestones when he defeated Manny Pacquiao by unanimous decision in May 2015.
Few other champions came close to matching those perfect records before their first loss late in their careers. Heavyweight champion Larry Holmes entered his September 1985 title defense with a 48-0 record before losing a decision to former light heavyweight champion and 1976 Olympic gold medalist Michael Spinks.
Brazilian legend Éder Jofre also went on a long unbeaten run before his first loss. Jofre entered his bantamweight title fight in 1965 with a record of 47-0-3 before losing by split decision to Fighting Harada of Japan.
Some champions managed to finish their careers undefeated. Welsh star Joe Calzaghe retired in November 2008 with a record of 46-0 (32 KOs) following a victory over Roy Jones Jr. and Bernard Hopkins during the last phase of his career. Earlier in his championship run, Calzaghe also defeated Denmark’s Mikkel Kessler in a super middleweight unification bout.
Long undefeated streaks have been seen throughout boxing history. According to the Ultimate Encyclopedia of Boxing by historian Harry Mullan, extended undefeated runs include Packey McFarland (97 fights), Fred Dyer (94 fights), Pedro Carrasco (93 fights), Sugar Ray Robinson (91 fights) and Julio César Chávez Sr. (90 battles).
Marciano’s 49-0 and Mayweather’s 50-0 remain the most famous records in boxing history. In a sport where even the greatest champions are often defeated during long matches, retiring undefeated is still a rare challenge.
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Last updated on 2026/03/14 at 3:08 PM
