MLB SlugFest 2003 More homeruns
Enable the “Rubber ball” code for a better chance of hitting homeruns.
Less homeruns
Enable the “Softball” code for less of a chance of hitting homeruns.
Easy ground balls and fly balls
Throw a fastball low for a ground out or a fastball high for a fly out. This works about 90% of the time.
Cheat Codes
At the match-up screen, press B, Y, and X to change the icons in the first, second, and third boxes respectively. The numbers in the following list indicate the number of times each button is pressed. After the icons have been changed, press the D-pad in the indicated direction to enable the code. For example, to enter 1-2-3 Left, press B, Y(2), X(3), Left. Note: More then one code may be activated per game.
| Result | Code |
| Infinite turbo | 4-4-4 Down |
| Maximum speed | 0-0-3 Left |
| Maximum power | 0-3-0 Left |
| Maximum batting | 3-0-0 Left |
| Rocket Park stadium | 3-2-1 Up |
| Roman Coliseum stadium | 3-3-3 Up |
| Eagle team | 2-1-2 Right |
| Horse team | 2-1-1 Right |
| Lion team | 2-2-0 Right |
| Pinto team | 2-1-0 Right |
| Todd McFarlane team | 2-2-2 Right |
| Terry Fitzgerald team | 3-3-3 Right |
| Extra time after plays | 1-2-3 Up |
| No fatigue | 3-4-3 Up |
| No contact | 4-3-3 Left |
| Log bat | 0-0-4 Up |
| Wiffle bat | 0-0-4 Right |
| Mace bat | 0-0-4 Left |
| Rubber ball | 2-4-2 Up |
| Softball | 2-4-2 Down |
| Big heads | 2-0-0 Right |
| Small heads | 2-0-0 Left |
| Tournament mode | 1-1-1 Down |