The 2004 Mr. Olympia contest was an International Federation of BodyBuilders professional bodybuilding competition and the feature event of Joe Weider's 2004 Olympia Weekend, held October 30 and 31, 2004, at the Mandalay Bay Arena in Las Vegas, Nevada.
This Mr. Olympia contest introduced a new Challenge Round to determine the final standings.
The top six competitors scores were discarded after round three, and only the final challenge round standings were used to decide the winner.
Ronnie Coleman won his seventh consecutive Mr. Olympia title.
Although he placed third in traditional scoring, Dexter Jackson lost to Gustavo Badell in the final challenge round, for a prize difference of $10,000.