| Competition: | Campeonato Brasileiro Série A |
| Season: | 2003 |
| Winners: | Cruzeiro 1st Campeonato Brasileiro title 2nd Brazilian title |
| Continentalcup1: | Copa Libertadores |
| Continentalcup2: | Copa Sudamericana |
| Matches: | 552 |
| Total Goals: | 1593 |
| League Topscorer: | Dimba (31 goals) |
| Average Attendance: | 15,629 |
| Prevseason: | 2002 |
| Nextseason: | 2004 |
The 2003 Campeonato Brasileiro Série A was the 47th edition of the Campeonato Brasileiro Série A. The first edition with only a double round-robin and no playoffs, it began on March 29, 2003, and reached its end on December 14. The competition was won by Cruzeiro Esporte Clube, who completed a treble.
The 24 teams played against each other twice. At the season finale, the team with the most accumulated points (3 for each win, 1 for a draw, none for a loss) was declared champion. The two worst teams were relegated to the Campeonato Brasileiro Série B of the following year.
| Pos. | Scorer | Club | Goals[1] |
|---|---|---|---|
| 1 | Goiás | 31 | |
| 2 |  Renaldo | Paraná | 30 |
| 3 | 29 | ||
| 4 | Alex | Cruzeiro | 23 |
| 5 |  Víctor Aristizábal | Cruzeiro | 22 |
| 6 | Marcel | Coritiba | 20 |
| 7 | Ilan | Atlético-PR | 16 |
| 8 | Deivid | Cruzeiro | 15 |
| Marquinhos | Paraná | 15 | |
| Wágner | Guarani | 15 | |
| Róbson | Paysandu | 15 |