December 13 – The Court of Arbitration for Sport bans American Tim Montgomery for two years in a case stemming from his involvement with the controversial "sports nutrition" center BALCO. Although Montgomery never tested positive for drugs, CAS found the circumstantial evidence against him overwhelming. It also struck all his results since 2001 from the records, including a then world-record time of 9.78.
Women's Division I – Baylor defeats Michigan State, 84–62, in the final. It is the first Women's National Title game in several years to not involve either Tennessee or UConn. Baylor coach Kim Mulkey-Robertson becomes the first woman to win NCAA Division I basketball titles as a player and coach.
May 7 – Diego Corrales defeats José Luis Castillo by 10th-round knockout, for the WBO-WBC lightweight title unification. Both men were exchanging a brutal amount of punishment throughout the fight, before a dramatic tenth round in which Corrales scored a TKO after getting knocked down twice. The fight was highly regarded as one of the greatest of all-time and won Ring Magazine fight of the year.
July 16 – Jermain Taylor, 2000 US Olympic Boxing bronze medalist, defeats Bernard Hopkins for the undisputed Middleweight Title ending Hopkins' 10 year title reign. Hopkins made 20 successful title defenses before losing to Taylor, the current record in the middleweight division, Carlos Monzón is second with 14 successful defenses.
January 10 – ICC World XI (344 for 8) beat the ACC Asian XI (232) by 112 runs to win the first of two scheduled one-day internationals for the World Cricket Tsunami Appeal; the second was never played. It is the first time an ODI has been played that has not been between two cricketing nations.
January 10 – Bangladesh beat Zimbabwe by 226 runs to record their first ever Test match victory.
February 16 – the 2004–05 NHL season was canceled by league commissioner Gary Bettman. This was the first time that a North American professional sports league had to cancel a season due to a labor dispute.
Finals to Pride GP 2005 lightweight and welterweight tournaments. Takanori Gomi becomes the Pride 2005 lightweight Grand Prix champion. Dan Henderson becomes the Pride 2005 welterweight Grand Prix champion.
In the November Tests, the All Blacks (New Zealand) score a "Grand Slam" by defeating all four Home Nations (Wales, Ireland, England, Scotland) while on tour. This is the first such Grand Slam for a Southern Hemisphere team since Australia did so in 1984, and the first for the All Blacks since 1978.
Asashōryū Akinori wins all six basho (tournament) in 2005 (a new record) and wins eighty-four bouts (out of ninety) setting a new record for victories in a single year. His seventh straight basho championship is also a new record.
