Juan Manuel Márquez Méndez (born August 23, 1973) is a Mexican former professional boxer who competed from 1993 to 2014.

In a career that spanned over twenty years, Márquez was known for being a fast and highly technical boxer who was exceptionally skilled at combinations and counterpunches, yet also willing to engage in slugfests with opponents.

His most notable bouts include his four-fight saga with Manny Pacquiao and his fight against fellow Mexican Marco Antonio Barrera.

Márquez remained undefeated for six years, compiling a 29–1 record that included wins against future champions Agapito Sanchez, Julio Gervacio and Alfred Kotey.

"[4] Márquez was WBO Featherweight Champion Naseem Hamed's mandatory challenger for 22 straight months.

[8] On September 18, 2004, Márquez made his first appearance on pay-per-view, being on the undercard of Bernard Hopkins vs. Oscar De La Hoya, defeating and retaining his unified titles against future champion Orlando Salido.

On May 7, 2005, he made his fourth title defense and first appearance on Showtime Championship Boxing, facing Victor Polo while walking away with a unanimous decision victory.

In August 2005, Márquez was stripped of his WBA and IBF unified Featherweight titles for his inability to defend them against various boxers after potential bouts failed to draw a bid.

In late 2006, Márquez captured the Interim WBO Featherweight title by defeating Thai boxer Terdsak Jandaeng.

On March 17, 2007, Márquez became the WBC Super Featherweight Champion by defeating Barrera in Las Vegas via unanimous decision,[11] by the official scores of 116–111, 116–111 and 118–109.

However, Barrios withdrew from the bout due to injury, prompting American boxer Rocky Juárez to challenge Márquez for the title on November 3, 2007, in a losing effort.

[12] Richard Schaefer, Golden Boy Promotions CEO, offered a $6 million guarantee to Pacquiao for a rematch.

On September 13, 2008, he defeated Casamayor in the 11th round after two knockdowns and captured his sixth world title in three different weight classes.

Referee Tony Weeks stepped in the bout and stopped the fight as he deemed Casamayor unable to continue.

[15] On February 28, 2009, Márquez defeated former WBA, WBO & IBF Lightweight Champion Juan Díaz by knockout.

Díaz opened a cut above Márquez's right eye in the fifth round and looked to control the bout, but Márquez responded by opening a gash above Díaz's right eye and stunning him with a left hook before the end of the eighth round.

The fight was scheduled to take place at 144-pound catch weight on July 18, 2009, at the MGM Grand Garden Arena; but was postponed due to a rib injury sustained by Mayweather.

Golden Boy CEO Richard Schaefer said the fight for Márquez's title was being planned for July 10 as the main event of an HBO PPV card.

[20] Prior to the bout, the WBO ordered the Márquez-Díaz winner to fight mandatory challenger Michael Katsidis.

[26][27] There was also a possibility of him moving up to light welterweight to face any of the titleholders at the time: Timothy Bradley, Devon Alexander or Amir Khan, all of whom were fighting on HBO.

[28] A few weeks after the Juan Díaz fight, Golden Boy Promotions officially announced that Márquez would defend his lightweight titles against mandatory challenger, WBO Interim Champion Michael Katsidis, on November 27, 2010, at the MGM Grand in Las Vegas and that the bout would be televised live on HBO Championship Boxing.

[31] Despite being knocked down in the third round, Márquez came back and defeated Katsidis by a ninth-round TKO to retain the lightweight belts.

[33] On January 4, the WBA no longer recognized Márquez as their Super Champion due to going 18 months without fighting a mandatory challenger as required by the organization's rules.

Many experts queried whether Ramos was hired to 'take a dive' (have the contest fixed or lose it on purpose) in order for Márquez to look good.

[40] Márquez attracted controversy by hiring strength and conditioning coach Angel "Memo Heredia" Hernandez, who had supplied performance-enhancing drugs to sprinters Marion Jones and Tim Montgomery in 2000.

[43] On April 14, 2012, Márquez defeated Ukrainian contender Serhiy Fedchenko via unanimous decision to capture the interim WBO light welterweight title by a clear margin with scores of 119–109, 118–110, 118–110.

[47] Márquez fought Timothy Bradley in a bout billed as 'The Conquerors' for his WBO welterweight title at the Thomas and Mack Center in Las Vegas, Nevada on October 12, 2013.

[50] Miguel Cotto Promotions told ESPN.com that negotiations had broken down on August 2 as both camps could not settle on what weight the fight would be.

I would have loved to do a final fight to say goodbye inside the ring, but I have to listen to my body, and it was telling me that the right moment to stop boxing is now."

He grew up in a rough and poor area of Iztacalco, many of his friends succumbing to gang violence and dying young while he went on to box.