| 1 | A | B | C | D | E | F | G |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 2 | List of undefeated boxing world champions |  |  |  |  |  |  |
| 3 | Boxer | Record | Weight class | Title(s) | Championship years | Title defenses | Notes |
| 4 | United States Jimmy Barry | 59–0–9 (2) | Bantamweight | World | 1894–1899 | 6 (3 draws) | - |
| 5 | United Kingdom Joe Calzaghe | 46–0–0 (0) | Super middleweight | WBO | 1997–2008 | 21 | Vacated title to move up to light heavyweight. |
| 6 | United Kingdom Joe Calzaghe | 46–0–0 (0) | Super middleweight | IBF | 2006 | 1 | Vacated title to fight Peter Manfredo Jr. instead of #1 contender Robert Stieglitz. |
| 7 | United Kingdom Joe Calzaghe | 46–0–0 (0) | Super middleweight | The Ring, lineal | 2006–2008 | 3 | Vacated titles to move up to light heavyweight. |
| 8 | United Kingdom Joe Calzaghe | 46–0–0 (0) | Super middleweight | WBA, WBC | 2007–2008 | 0 | Vacated titles to move up to light heavyweight. |
| 9 | United Kingdom Joe Calzaghe | 46–0–0 (0) | Light heavyweight | The Ring | 2008 | 1 | Retired and vacated title. |
| 10 | South Korea Kim Ji-won | 16–0–2 (0) | Super bantamweight | IBF | 1985–1986 | 4 | - |
| 11 | Romania Mihai Leu | 28–0–0 (0) | Welterweight | WBO | 1997 | 1 | Retired from boxing due to an injury. |
| 12 | Mexico Ricardo López | 51–0–1 (0) | Minimumweight | WBC | 1990–1998 | 22 | Vacated title to move up to light flyweight. |
| 13 | Mexico Ricardo López | 51–0–1 (0) | Minimumweight | WBO | 1997–1998 | 0 | Unified WBC and WBO titles. Stripped of WBO title for saying he wanted to give the belt to his father. |
| 14 | Mexico Ricardo López | 51–0–1 (0) | Minimumweight | WBA | 1998 | 0 | Vacated title to move up to junior flyweight. |
| 15 | Mexico Ricardo López | 51–0–1 (0) | Light flyweight | IBF | 1999–2002 | 2 | - |
| 16 | United States Rocky Marciano | 49–0–0 (0) | Heavyweight | World | 1952–1956 | 6 | - |
| 17 | United Kingdom Terry Marsh | 26–0–1 (0) | Light welterweight | IBF | 1987 | 1 | Retired from boxing due to epilepsy. |
| 18 | United States Floyd Mayweather Jr. | 50–0–0 (0) | Super featherweight | WBC | 1998–2002 | 8 | Vacated title to move up to lightweight. |
| 19 | United States Floyd Mayweather Jr. | 50–0–0 (0) | Lightweight | WBC | 2002–2004 | 3 | Vacated title to move up to light welterweight. |
| 20 | United States Floyd Mayweather Jr. | 50–0–0 (0) | Light welterweight | WBC | 2005–2006 | 0 | Vacated title to move up to welterweight. |
| 21 | United States Floyd Mayweather Jr. | 50–0–0 (0) | 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. |
| 22 | United States Floyd Mayweather Jr. | 50–0–0 (0) | Light middleweight | WBA, WBC | 2007, 2012–2015, 2017 | 2 | Retired at 49–0 in 2015; returned in 2017 for non-title McGregor fight and then retired again. |
| 23 | Republic of Ireland Jack McAuliffe | 30–0–5 (1) | Lightweight | World | 1886–1893 | 7–0–2 (0) | - |
| 24 | Germany Sven Ottke | 34–0–0 (0) | Super middleweight | IBF | 1998–2004 | 21 | - |
| 25 | Germany Sven Ottke | 34–0–0 (0) | Super middleweight | WBA | 2003–2004 | 4 | Defended IBF title and defeated WBA champion to become WBA Super champion. |
| 26 | Russia Dmitry Pirog | 20–0–0 (0) | Middleweight | WBO | 2010–2012 | 3 | Retired from boxing due to chronic back injuries. |
| 27 | Namibia Harry Simon | 31–0–0 (0) | Light middleweight | WBO | 1998–2001 | 4 | Vacated title to move up to middleweight. |
| 28 | Namibia Harry Simon | 31–0–0 (0) | Middleweight | WBO | 2002 | 0 | Won WBO interim middleweight title in 2001 and the outright title in 2002. Stripped of title at 22–0 when he was unable to defend it due to injuries suffered in a car crash. |
| 29 | Thailand Pichit Sitbangprachan | 24–0–0 (0) | Flyweight | IBF | 1992–1994 | 5 | Retired at 21–0 and then made a comeback. |
| 30 | Venezuela Edwin Valero | 27–0–0 (0) | Super featherweight | WBA | 2006–2008 | 4 | Vacated title to move up to lightweight. |
| 31 | Venezuela Edwin Valero | 27–0–0 (0) | Lightweight | WBC | 2009–2010 | 2 | Vacated title to move up to light welterweight. Committed suicide after allegedly killing his wife in 2010. |
| 32 | United States Andre Ward | 32–0–0 (0) | Super middleweight | WBA | 2009–2015 | 6 | Vacated titles in 2015 to move up to light heavyweight. |
| 33 | United States Andre Ward | 32–0–0 (0) | Super middleweight | WBC, The Ring, lineal | 2011–2015 | 1 (WBC), 2 (The Ring, lineal) | Vacated titles in 2015 to move up to light heavyweight. |
| 34 | United States Andre Ward | 32–0–0 (0) | Light heavyweight | WBA, WBO, The Ring, lineal | 2016–2017 | 1 (WBA, IBF, WBO), 0 (The Ring, lineal) | - |

Question: What achievements do Edwin Valero have?
Answer: Edwin Valero was an undefeated former world champion in two weight classes at the time of his death, having held the WBA super featherweight title from 2006 to 2008 and the WBC lightweight title from 2009 to 2010.