Floyd Mayweather Jr. has yet to be born.
Floyd Mayweather Jr. . Widely considered to be one of the greatest boxers of all time , undefeated as a professional , and a five-division world champion , Mayweather won fifteen world titles and the lineal championship in four different weight classes ( twice at welterweight ) . In 2016 , Mayweather was ranked by ESPN as the greatest boxer , pound for pound , of the last 25 years . He is also regarded as the best defensive boxer in the sport , as well as being the most accurate puncher since the existence of CompuBox , having the highest plus -- minus ratio in recorded boxing history . He finished his career with a record of 26 wins without a loss or draw in world title fights ( 10 by KO ) ; 23 wins ( 9 KOs ) in lineal title fights ; 24 wins ( 7 KOs ) against former or current world titlists ; 12 wins ( 3 KOs ) against former or current lineal champions ; and 2 wins ( 1 KO ) against International Boxing Hall of Fame inductees .