While most rankings have a variety of judging criteria, this list has just one - sheer toughness and grit. Let's get right into the top 10.
10 Pancho Villa
Professional record: 89-8-4
To start off these rankings, we go back to the early 1900s and pay homage to Filipino icon Pancho Villa. Standing at just 5'1" tall, his size did not stop him being one of the most formidable fighters of his era. He tragically passed away at the age of just 23, but before that would have over 100 fights in his young career, with 89 victories. Famously, Villa was never knocked out, and his name has become legendary in the sport, where he is now a member of the coveted International Boxing Hall of Fame.
9 Gennady Golovkin
Professional record: 42-2-1
8 Evander Holyfield
Professional record: 44-10-2
7 Larry Holmes
Professional record: 69-6
Speaking of Holmes, he just edges Holyfield and comes in at seventh place in the list of the toughest boxers of all time. The 6'3" heavyweight fought into his 50s and faced almost every big name available to him. His left jab is etched into the sport's history and is unanimously considered one of the toughest to face, with few fighters ever managing to emulate the ferocity of the Holmes jab. Holmes would win his first 48 fights in a row on his way to winning the world heavyweight championship.
6 Saul 'Canelo' Alvarez
Professional record: 62-2-2
5 Mike Tyson
Professional record: 50-7
When Tyson fought, the world stood still and watched. His fights were often short, with many ending in the first round, showcasing his ability to finish opponents quickly. Tyson's intimidating presence, both physically and psychologically, played a significant role; his intense stare and aggressive trash-talking were part of his strategy.
4 Muhammad Ali
Professional record: 56-5
3 Marvin Hagler
Professional record: 62-3-2
Just making it into the podium positions is one of the most exciting fighters in the history of the middleweight division. 'Marvelous' Marvin Hagler was a joy to watch, combining efficiency and power with pure entertainment. Standing at 5'9", Hagler proves further that the smaller guys in the sport could be tougher than some of the giant heavyweights. Perhaps best known for his iron chin, Hagler was never defeated by stoppage in his entire career, and has famous victories under his belt as well as being part of what many believe to be the best fight of all time, when he faced off against Thomas Hearns in 1985.
2 George Foreman
Professional record: 76-5
We go back to the heavyweight division for the second-toughest fighter of all time. 'Big' George Foreman stood at 6'4" and was a ferocious force inside the ring. He is known for fighting across multiple eras, with his career spanning a ridiculous 28 years. In terms of famous and memorable fights, Foreman was part of perhaps the best of the bunch, facing Muhammad Ali in the 'Rumble in the Jungle' in 1974, which was his only career stoppage defeat.
1 George Chuvalo
Professional record: 73-18-2
Chuvalo may not have the widespread fame of Ali or Tyson, but he is considered by many as the toughest man to ever lace a pair of gloves. He fought the best of the best whilst competing in the golden era of heavyweight boxing. The likes of Ali, Joe Frazier, George Foreman and many more could not knock this guy down. In fact, in his 93 career fights, he was never knocked down once, only losing inside the distance when stopped on his feet.