Here is a list of all the Heavyweight Boxing Champions from 1937-2021
- Joe Louis (1937-1949)
- Ezzard Charles (1950-1951)
- Rocky Marciano (1952-1956)
- Floyd Patterson (1956-1959, 1960-1962)
- Ingemar Johansson (1959-1959)
- Sonny Liston (1962-1964)
- Cassius Clay (1964-1964)
- Muhammad Ali (1964-1967, 1974-1978)
- Joe Frazier (1970-1973)
- George Foreman (1973-1974)
- Muhammad Ali (1974-1978)
- Leon Spinks (1978-1978)
- Muhammad Ali (1978-1979)
- Larry Holmes (1978-1985)
- Michael Spinks (1985-1985)
- Mike Tyson (1986-1990, 1996-1996)
- Evander Holyfield (1990-1990, 1992-1992, 1993-1993, 1996-1996, 1997-1997)
- Riddick Bowe (1992-1993)
- Michael Moorer (1994-1994)
- George Foreman (1994-1994)
- Mike Tyson (1996-1996)
- Evander Holyfield (1996-1997)
- Lennox Lewis (1997-2000, 2001-2004)
- Hasim Rahman (2001-2001)
- Vitali Klitschko (2004-2005, 2008-2012, 2013-2013)
- Corrie Sanders (2003-2003)
- Lamon Brewster (2004-2004)
- Oleg Maskaev (2005-2005)
- Sergei Liakhovich (2006-2006)
- Sultan Ibragimov (2007-2008)
- Ruslan Chagaev (2009-2009)
- David Haye (2009-2011)
- Wladimir Klitschko (2011-2015)
- Tyson Fury (2015-2015, 2018-2018)
- Deontay Wilder (2015-2019, 2021-2021)
- Anthony Joshua (2016-2019,2021-2021)
Here is a list of all the Middle Weight Boxing Champions from 1897-Present
- Bob Fitzsimmons (1897-99)
- Tommy Ryan (1899-1905)
- Stanley Ketchel (1908-10)
- Harry Greb (1923-26)
- Mickey Walker (1926-31)
- Tony Zale (1941-48)
- Rocky Graziano (1947-48)
- Carmen Basilio (1957-58)
- Gene Fullmer (1957-59, 1960-61)
- Paul Pender (1960-62)
- Sugar Ray Robinson (1951-52, 1955-58)
- Dick Tiger (1962-63, 1964-66)
- Nino Benvenuti (1967-69, 1970-72)
- Carlos Monzon (1970-77)</li
- Marvin Hagler (1980-87)
- Thomas Hearns (1982-85)
- Michael Nunn (1987-91)
- Gerald McClellan (1990-91)
- James Toney (1991-94, 2003-05)
- Bernard Hopkins (1994-2005, 2011-12)
- Kelly Pavlik (2007-08, 2010)
- Sergio Martinez (2010-14)
- Canelo Alvarez (2015-Present)
Here is a list of all the Lightweight Boxing Champions from 1900-Present
- Bob Fitzsimmons (1900-1903)
- Terry McGovern (1901-1903)
- Joe Gans (1902-1908)
- Battling Nelson (1905-1908)
- Ad Wolgast (1909-1912)
- Willie Ritchie (1912-1914)
- Benny Leonard (1917-1925)
- Tony Canzoneri (1930-1935)
- Lou Ambers (1935-1938)
- Henry Armstrong (1938-1940)
- Ike Williams (1947-1951)
- Sandy Saddler (1948-1952)
- Paddy DeMarco (1954-1955)
- Joe Brown (1956-1962)
- Carlos Ortiz (1962-1965)
- Ismael Laguna (1967-1968)
- Roberto Duran (1972-1979)
- Ray Leonard (1976-1979)
- Aaron Pryor (1982-1985)
- Livingstone Bramble (1984-1985)
- Julio Cesar Chavez (1987-1998)
- Oscar De La Hoya (1995-2000)
- Floyd Mayweather Jr. (1998-2015)
- Juan Manuel Marquez (2007-2012)
- Mikey Garcia (2013-2019)
- Teofimo Lopez (2020-Present)
Please note this list is not exhaustive and only includes champions recognized by major governing bodies such as the WBA, WBC, IBF, and WBO.