| Competition: | J.League Division 1 |
| Season: | 2004 |
| Winners: | Yokohama F. Marinos 3rd J.League title 5th Japanese title |
| Continentalcup1: | AFC Champions League |
| Continentalcup1 Qualifiers: | Yokohama F. Marinos Júbilo Iwata |
| League Topscorer: | Emerson Sheik (27 goals) |
| Matches: | 240 |
| Total Goals: | 744 |
| Highest Attendance: | 58,334 (Round 24, Reds vs. Marinos) |
| Lowest Attendance: | 4,429 (Round 5, Gamba vs. JEF United) |
| Average Attendance: | 18,965 |
| Prevseason: | 2003 |
| Nextseason: | 2005 |
The 2004 J.League Division 1 season was the 12th season of the J.League Division 1. The league fixture began on March 13 and ended on December 12. The Suntory Championship took place on December 5 and 11, followed by the first ever J. League promotion/relegation series on December 4 and 12.
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The following sixteen clubs participated in J.League Division 1 during 2004 season. Of these clubs, Albirex Niigata and Sanfrecce Hiroshima were newly promoted from Division 2.
In the 2004 season, the league was conducted split-season format, 1st Stage and 2nd Stage. In each stage, sixteen clubs played in a single round-robin format, a total of 15 games per club (per stage). A club received 3 points for a win, 1 point for a tie, and 0 points for a loss. The club were ranked by points, and tie breakers are, in the following order:
A draw would be conducted, if necessary. The club that finished at the top of the table is declared stage champion and qualifies for the Suntory Championship. The first stage winner, hosts the first leg in the championship series. If a single club wins both stages, the club is declared the season champions and championship series will not be held. Meanwhile, the last-placed (16th-placed) club must play Pro/Rele Series at the end of the season.
Yokohama F. Marinos won the first stage and thus hosted the first game. They won the first leg by 1–0 thanks to Ryuji Kawai's goal. In the second leg, Alessandro Santos scored from the free kick in 76th minute to level the aggregate score. The clubs played in sudden death extra time, however neither club could break the scoreline. Yokohama upset the home club in the penalties winning them and series overall.
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| Position | Footballer | Club | Nationality | |
|---|---|---|---|---|
| GK | Yoichi Doi (1) | FC Tokyo | ||
| DF | Dutra (2) | Yokohama F. Marinos | ||
| DF | Marcus Tulio Tanaka (1) | Urawa Red Diamonds | ||
| DF | Yuji Nakazawa (3) | Yokohama F. Marinos | ||
| MF | Daisuke Oku (3) | Yokohama F. Marinos | ||
| MF | Makoto Hasebe (1) | Urawa Red Diamonds | ||
| MF | Mitsuo Ogasawara (4) | Kashima Antlers | ||
| MF | Yasuhito Endō (2) | Gamba Osaka | ||
| FW | Emerson Sheik (3) | Urawa Red Diamonds | ||
| FW | Marques (1) | Nagoya Grampus Eight | ||
| FW | Masashi Oguro (1) | Gamba Osaka |
