Check out my rankings within each division by clicking on the links below. If there is a lineal champion in a weight class, he is ranked No. 1.
Who is the best fighter regardless of weight class? See ESPN's pound-for-pound rankings.
For a list of the current champions in all weight classes, click here.
Note: Results through May 16. In an effort to provide the most up-to-date rankings, ESPN.com's division-by-division boxing rankings will be updated every Tuesday.
More divisional rankings
Middleweight - Junior middleweight - Welterweight - Junior welterweight
Lightweight - Junior lightweight - Featherweight - Junior featherweight
Bantamweight - Junior bantamweight - Flyweight - Junior flyweight/Strawweight
HEAVYWEIGHT DIVISION (UNLIMITED)
1. Anthony Joshua (19-0)
In 2012, Joshua won the Olympic super heavyweight gold medal for Great Britain, became a megastar at home and steamrolled his way to becoming a unified world titleholder. He faced by far the biggest challenge of his career on April 29 when he met former longtime world champion Wladimir Klitschko before a sellout crowd of 90,000 at London's Wembley Stadium in one of the greatest atmospheres ever, and they produced an all-time classic heavyweight title fight that more than lived up to the hype. Joshua survived a knockdown and many difficult moments to score three total knockdowns in a dramatic 11th-round knockout victory as he retained his title and also claimed a vacant belt. Klitschko has the right to a rematch, so that very well could be next for Joshua. Whomever he fights it's sure to be an entertaining fight.
2. Deontay Wilder (38-0)
Wilder, a tremendous puncher, has scored knockouts in all five of his title defenses, including on Feb. 25 when he stopped Gerald Washington in the fifth round. It was Wilder's first fight since knocking out Chris Arreola in July; Wilder broke his right hand and tore his right biceps in that bout and required surgery to repair both injuries. He hopes to meet Joseph Parker (22-0) or Anthony Joshua (19-0) in a title unification fight next, but he might instead have to fight a pointless mandatory defense against undeserving Bermane Stiverne (25-2-1), the man he easily outpointed for the belt in January 2015.
3. Wladimir Klitschko (64-5)
During his 9½-year title reign -- second longest in heavyweight history -- Klitschko successfully defended the title 18 times, third most in division history. He had an 11½-year undefeated run and won 22 fights in a row. But then he lost the title to England's Tyson Fury in November 2015 in a terrible fight and many thought Klitschko had grown old before their eyes. After a rematch with Fury was twice called off, Klitschko returned on April 29 and showed that he still has something left at age 41 as he came within a whisker of knocking out Anthony Joshua to reclaim two belts in an epic fight. He had Joshua down and in huge trouble but eventually lost by 11th-round knockout. Klitschko has the contractual right to a rematch. Most expect he will exercise the option, but he is taking his time to think about his decision.
4. Luis Ortiz (27-0)
A 6-foot-4, 240-pound southpaw with raw power, Ortiz, a Cuban defector with tons of amateur experience, signed with adviser Al Haymon in March and was quickly added to the Shawn Porter-Andre Berto undercard to face journeyman Derric Rossy (31-12) on April 22. However, Ortiz suffered a thumb injury and his fight was scrapped, though he remains a mandatory challenger for for Anthony Joshua
5. Joseph Parker (23-0)
When Tyson Fury vacated his two sanctioning-body belts, it put New Zealand's Parker in position to face Andy Ruiz Jr. for one of the belts on Dec. 10. In one of the biggest sporting events in New Zealand history, Parker overcame a slow start and managed to edge Ruiz by majority decision to claim the title and become his country's first heavyweight titleholder. Parker's first defense was scheduled to be a mandatory against Hughie Fury (20-0), Tyson's first cousin, in New Zealand. But Fury pulled out with a supposed back injury two weeks before the bout, leaving Parker to face substitute and former sparring partner Razvan Cojanu, of Romania, on May 6. Parker won a wide decision in an unimpressive performance and boring fight.
6. Kubrat Pulev (25-1)
Bulgaria's Pulev, who got knocked out in a title shot against then-world champion Wladimir Klitschko in November 2014, has won four in a row since. On Dec. 3, Pulev's first fight in his home country, he hammered washed-up, out-of-shape former titlist Samuel Peter for three rounds. Peter quit with an apparent arm injury just after the bell rang to begin the fourth round. Pulev returned for his fifth win in a row, also at home, as he rolled to a near-shutout decision against journeyman Kevin Johnson on April 28 to remain in position as one of Anthony Joshua's mandatory challengers.
7. Andy Ruiz Jr. (29-1)
Ruiz, who has tremendous hand speed but is not always in the best condition, traveled to New Zealand to face Joseph Parker for a vacant title on Dec. 10 in a bid to become the first heavyweight of Mexican descent to win a world title. He came up just short of the goal, dropping a majority decision in a fight that was exceptionally close.
8. Dillian Whyte (20-1)
Whyte, the former British champion, outpointed former world title challenger Dereck Chisora on Dec. 10 in an epic slugfest that was one of the best fights of 2016. The victory was Whyte's fourth in a row since a knockout loss to Anthony Joshua in December 2015, and he deserves another meaningful fight. He was due back to face Poland's Mariusz Wach (33-2), a former world title challenger, in an interesting fight on June 3 but Whyte suffered a foot injury, forcing the card to be postponed.
9. Dominic Breazeale (18-1)
A 2012 U.S. Olympian, Breazeale gave a good account of himself in a seventh-round knockout loss challenging Anthony Joshua for his world title in June 2016 and bounced back to stop previously undefeated Izuagbe Ugonoh in the fifth round of a hellacious see-saw battle on Feb. 25 in a candidate for fight of the year.
10. Jarrell "Big Baby" Miller (18-0-1)
New York's Miller has a big body, a big punch and a big personality. In August 2016, he knocked out battle-tested veteran Fred Kassi in the third round but has not fought since because he is embroiled in a dispute with promoter Dmitry Salita. They need to work things out already.