| Date | 15 August 2004 | |
|---|---|---|
| Status | Olympic | |
| Location | Olympiako Gymnastirio Ano Liosion, Ano Liossia | |
| Participants | 31 from 31 countries | |
| Format | Two single-elimination pools, with winner of each pool advanced to the final. All judoka losing to the finalists in each pool advanced to repêchage pools, with the winners of the repêchage pools earning bronze medals. | |
The last two World Championships had been won by Iran’s Arash Miresmaeili. But at the weigh-in he was two full kilograms over the class limit, and was disqualified. The Iranian News Agency quoted Miresmaeli as saying he had done this deliberately, rather than face his first-round opponent, Israel’s Ehud Vaks. On his return home, Miresmaeli was given $125,000, the amount given to Iranian gold medal winners, and a ticket to visit Mecca. The Iranian state news agency IRNA quoted then Iranian President Mohammad Khatami as saying, “Miresmaeili’s actions would be recorded in the history of Iranian glories.” Mahmoud Ahmadinejad, then the mayor of Tehran, and later Iran’s President, said that although Miresmaeili “did not get a gold medal, he earned eternal honor by his refusal.” The International Judo Federation investigated this incident, but strangely, when they did so, Miresmaeli claimed he had made no such statements and no sanction was given. Miresmaeli did compete at the 2008 Olympic Games, after winning bronze medals at the 2005 and 2007 World Championships, but finished only =9th.
In his absence there was no favorite in Athina and no real story to the competition. Japan’s Masato Uchishiba, who had won at the World University Games in 2001, won the gold medal. In 2008 he would return to defend his gold medal, after winning a silver at the 2005 Worlds. In February 2013 Uchishiba was convicted of raping a student he had been coaching. The incident occurred in 2011 and Uchishiba maintained that it was consensual sex, but the court ruled that he had assaulted her while she was alseep and he was sentenced to five years in prison.
| Date | 15 August 2004 |
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| Date | 15 August 2004 |
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| Match | Date/Time | Competitor | NOC | Result | Competitor | NOC | |
|---|---|---|---|---|---|---|---|
| Match #1 | 15 Aug | Yordanis Arencibia | CUB | Waza-ari | Ludwing Ortiz | VEN | |
| Match #2 | 15 Aug | Heath Young | AUS | Waza-ari | Juan José Paz | BOL | |
| Match #3 | 15 Aug | Miklós Ungvári | HUN | Ippon | Elçin Mehdi İsmayılov | AZE | |
| Match #4 | 15 Aug | João Pina | POR | Ippon | Musa Nastuiev | UKR | |
| Match #5 | 15 Aug | Óscar Peñas | ESP | Ippon | Melvin Méndez | PUR | |
| Match #6 | 15 Aug | DoDo Krnáč | SVK | Waza-ari-wasete ippon | Abdou Alassane Dji Bo | NIG | |
| Match #7 | 15 Aug | Amar Meridja | ALG | Ippon | Ameen Mohamed El-Hady | EGY | |
| Match #8 | 15 Aug | Ehud Vaks | ISR | Fusen-gachi | Arash Miresmaeili | IRI | walkover |
| Date | 15 August 2004 |
|---|
| Match | Date/Time | Competitor | NOC | Result | Competitor | NOC | |
|---|---|---|---|---|---|---|---|
| Match #1 | 15 Aug | Yordanis Arencibia | CUB | Ippon | Heath Young | AUS | |
| Match #2 | 15 Aug | João Pina | POR | Yuko | Miklós Ungvári | HUN | |
| Match #3 | 15 Aug | DoDo Krnáč | SVK | Ippon | Óscar Peñas | ESP | |
| Match #4 | 15 Aug | Amar Meridja | ALG | Yuko | Ehud Vaks | ISR |
| Date | 15 August 2004 |
|---|
| Match | Date/Time | Competitor | NOC | Result | Competitor | NOC | |
|---|---|---|---|---|---|---|---|
| Match #1 | 15 Aug | Yordanis Arencibia | CUB | Ippon | João Pina | POR | |
| Match #2 | 15 Aug | DoDo Krnáč | SVK | Ippon | Amar Meridja | ALG |
| Date | 15 August 2004 |
|---|
| Match | Date/Time | Competitor | NOC | Result | Competitor | NOC | |
|---|---|---|---|---|---|---|---|
| Match #1 | 15 Aug | DoDo Krnáč | SVK | Ippon | Yordanis Arencibia | CUB |
| Date | 15 August 2004 |
|---|
| Match | Date/Time | Competitor | NOC | Result | Competitor | NOC | |
|---|---|---|---|---|---|---|---|
| Match #1 | 15 Aug | Ludwing Ortiz | VEN | Ippon | Heath Young | AUS | |
| Match #2 | 15 Aug | Óscar Peñas | ESP | Yuko | Abdou Alassane Dji Bo | NIG | |
| Match #3 | 15 Aug | João Pina | POR | Yuko | Ludwing Ortiz | VEN | |
| Match #4 | 15 Aug | Óscar Peñas | ESP | Yuko | Amar Meridja | ALG | |
| Match #5 | 15 Aug | Óscar Peñas | ESP | Yuko | João Pina | POR | |
| Match 3/5 | 15 Aug | Georgi Georgiev | BUL | Koka | Óscar Peñas | ESP |
| Date | 15 August 2004 |
|---|
| Date | 15 August 2004 |
|---|
| Match | Date/Time | Competitor | NOC | Result | Competitor | NOC | |
|---|---|---|---|---|---|---|---|
| Match #1 | 15 Aug | Magomed Dzhafarov | RUS | Yuko | Alex Ottiano | USA | |
| Match #2 | 15 Aug | Henrique Guimarães | BRA | Ippon | Bang Gwi-Man | KOR | |
| Match #3 | 15 Aug | Gantömöriin Dashdavaa | MGL | Waza-ari | Georgios Vazagkasvili | GRE | |
| Match #4 | 15 Aug | Masato Uchishiba | JPN | Ippon | Jorge Lencina | ARG | |
| Match #5 | 15 Aug | Muratbek Kipshakbayev | KAZ | Waza-ari | Juan Carlos Jacinto | DOM | |
| Match #6 | 15 Aug | Miloš Mijalković | SCG | Waza-ari | Murat Kalikulov | UZB | |
| Match #7 | 15 Aug | Bektaş Demirel | TUR | Ippon | Larbi Benboudaoud | FRA | |
| Match #8 | 15 Aug | Georgi Georgiev | BUL | Ippon | Davit Margoshvili | GEO |
| Date | 15 August 2004 |
|---|
| Match | Date/Time | Competitor | NOC | Result | Competitor | NOC | |
|---|---|---|---|---|---|---|---|
| Match #1 | 15 Aug | Magomed Dzhafarov | RUS | Waza-ari | Henrique Guimarães | BRA | |
| Match #2 | 15 Aug | Masato Uchishiba | JPN | Ippon | Gantömöriin Dashdavaa | MGL | |
| Match #3 | 15 Aug | Muratbek Kipshakbayev | KAZ | Koka | Miloš Mijalković | SCG | |
| Match #4 | 15 Aug | Georgi Georgiev | BUL | Ippon | Bektaş Demirel | TUR |
| Date | 15 August 2004 |
|---|
| Match | Date/Time | Competitor | NOC | Result | Competitor | NOC | |
|---|---|---|---|---|---|---|---|
| Match #1 | 15 Aug | Masato Uchishiba | JPN | Ippon | Magomed Dzhafarov | RUS | |
| Match #2 | 15 Aug | Georgi Georgiev | BUL | Waza-ari | Muratbek Kipshakbayev | KAZ |
| Date | 15 August 2004 |
|---|
| Match | Date/Time | Competitor | NOC | Result | Competitor | NOC | |
|---|---|---|---|---|---|---|---|
| Match #1 | 15 Aug | Masato Uchishiba | JPN | Ippon | Georgi Georgiev | BUL |
| Date | 15 August 2004 |
|---|
| Match | Date/Time | Competitor | NOC | Result | Competitor | NOC | |
|---|---|---|---|---|---|---|---|
| Match #1 | 15 Aug | Jorge Lencina | ARG | Ippon | Gantömöriin Dashdavaa | MGL | |
| Match #2 | 15 Aug | Davit Margoshvili | GEO | Waza-ari | Bektaş Demirel | TUR | |
| Match #3 | 15 Aug | Jorge Lencina | ARG | Ippon | Magomed Dzhafarov | RUS | |
| Match #4 | 15 Aug | Davit Margoshvili | GEO | Yuko | Muratbek Kipshakbayev | KAZ | |
| Match #5 | 15 Aug | Davit Margoshvili | GEO | Ippon | Jorge Lencina | ARG | |
| Match 3/5 | 15 Aug | Yordanis Arencibia | CUB | Waza-ari-wasete ippon | Davit Margoshvili | GEO |
| Date | 15 August 2004 |
|---|
| Match | Date/Time | Competitor | NOC | Result | Competitor | NOC | |
|---|---|---|---|---|---|---|---|
| Match 1/2 | 15 Aug | Masato Uchishiba | JPN | Ippon | DoDo Krnáč | SVK |