List of undefeated boxing world champions

Table columns:
Boxer
Record
Weight class
Title(s)
Championship years
Title defenses
Notes

Table rows:
cells: Jimmy Barry[1]
59–0–9 (2)
Bantamweight
World
1894–1899
6 (3 draws)
cells: Joe Calzaghe[2]
46–0–0 (0)
Super middleweight
WBO
1997–2008
21
Vacated title to move up to light heavyweight.
cells: IBF
2006
1
Vacated title to fight Peter Manfredo Jr. instead of #1 contender Robert Stieglitz.
cells: The Ring, lineal
2006–2008
3
Vacated titles to move up to light heavyweight.
cells: WBA, WBC
2007–2008
0
cells: Light heavyweight
The Ring
2008
1
Retired and vacated title.
cells: Kim Ji-won[3]
16–0–2 (0)
Super bantamweight
IBF
1985–1986
4
cells: Mihai Leu[4]
28–0–0 (0)
Welterweight
WBO
1997
1
Forced to retire from boxing due to an injury.
cells: Ricardo López[3]
51–0–1 (0)
Minimumweight
WBC
1990–1998
22
Vacated title to move up to light flyweight.
cells: WBO
1997–1998
0
Unified WBC and WBO titles. Stripped of WBO title for saying he wanted to give the belt to his father.[5]
cells: WBA
1998
0
Vacated title to move up to junior flyweight.
cells: Light flyweight
IBF
1999–2002
2
cells: Rocky Marciano[3][6]
49–0–0 (0)
Heavyweight
World
1952–1956
6
cells: Terry Marsh[3][4]
26–0–1 (0)
Light welterweight
IBF
1987
1
Forced to retire due to epilepsy.
cells: Floyd Mayweather Jr.[7]
50–0–0 (0)
Super featherweight
WBC
1998–2002
8
Vacated title to move up to lightweight.
cells: Lightweight
WBC
2002–2004
3
Vacated title to move up to light welterweight.
cells: Light welterweight
WBC
2005–2006
0
Vacated title to move up to welterweight.
cells: Welterweight
WBA, WBC
2006–2008, 2011–2015
8
Retired at 49–0 in 2015; returned in 2017 for non-title McGregor fight and then retired again.
cells: Light middleweight
WBA, WBC
2007, 2012–2015, 2017
2
cells: Jack McAuliffe[8]
30–0–5 (1)
Lightweight
World
1886–1893
7–0–2 (0)
cells: Sven Ottke[3]
34–0–0 (0)
Super middleweight
IBF
1998–2004
21
cells: WBA
2003–2004
4
Defended IBF title and defeated WBA champion to become WBA Super champion.
cells: Dmitry Pirog
20–0–0 (0)
Middleweight
WBO
2010–2012
3
Forced to retire from boxing due to chronic back injuries.
cells: Harry Simon[9]
30–0–0 (0)
Light middleweight
WBO
1998–2001
4
Vacated title to move up to middleweight.
cells: Middleweight
WBO
2002
0
Won WBO interim middleweight title in 2001 and the outright title in 2002. Stripped of title at 29–0 when he was unable to defend it due to injuries suffered in a car crash. Had one more non-title fight before retiring.
cells: Pichit Sitbangprachan[9]
24–0–0 (0)
Flyweight
IBF
1992–1994
5
Retired at 21–0 and then made a comeback.
cells: Edwin Valero[10]
27–0–0 (0)
Super featherweight
WBA
2006–2008
4
Vacated title to move up to lightweight.
cells: Lightweight
WBC
2009–2010
2
Vacated title to move up to light welterweight. Committed suicide after allegedly killing his wife in 2010. All 27 fights were knockout wins.
cells: Andre Ward[11]
32–0–0 (0)
Super middleweight
WBA
2009–2015
6
Vacated titles in 2015 to move up to light heavyweight.
cells: WBC, The Ring, lineal
2011–2015
1 (WBC), 2 (The Ring, lineal)
cells: Light heavyweight
WBA, WBO, The Ring, lineal
2016–2017
1 (WBA, IBF, WBO), 0 (The Ring, lineal)

Questions about this table:
originalText: who has the most undefeated wins in boxing
answer: answerTexts: Jimmy Barry