Secret Stadiums:
At the 'controllers' select screen, press Square & access the 'Stadium Select' option. When the list of stadiums appears, press L2, L1, R1, R1, R2, you’ll hear a voice say 'Triple Play '99'. Now scroll to the right & you’ll find 3 'secret' stadiums (Ancient Rome, Neo Vancouver & Anytown USA).

Commercials Cheat:
Anytime during the game hold down L1 + R1, then press Left, Right, Square, Circle & the announcer will say a commercial, which are sometimes funny.

Power Hitter:
At the 'Create Player' screen, enter the name: Erik Kiss & this guy will hit a homerun every time.

Hit A Homerun Every Time:
When in game play, hold R1, L1, R2, L2 & press Triangle, Square, Triangle, Circle, X, Square while still holding the top buttons, press Left, Right.

Automatic Strikeout:
When in game play, hold R1, L1, R2, L2 & press Up, Down, Triangle, Square, Triangle, Circle, X, Square. Then you can throw a ball & strike your opponent out each time.

Various Codes - Hold L1, L2, R1, R2 while entering the code:
A Crowd Comment       Up, Triangle, Down, X.
A Weather Comment    X, Down, Triangle, Up.
A Sponsor Comment    Left, Square, Right, Circle.
Play Nickname Game    Circle, Right, Square, Left.
Some Baseball History Up, Triangle, Right, Circle.
Stadium Information      Down, X, Right, Circle.
A Crowd Applause        Triangle, Up, Up, Triangle.
A Crowd Cheer                Square, Left, Left, Square.
A Crowd Ooh                 X, Down, Down, X.
A Crowd Boo                   Circle, Right, Right, Circle.
The Usercam                   Right, Left, Up, Down, Right, Left.
Ovstat The Batter          Left, Square, Up, Triangle.

Blast A 900ft Bunt Out Of The Park:
To fake all your friends out with the power bunt, hold all 4 shoulder buttons during you batting session, while holding these, press Triangle, Square, Triangle, Circle, X, Square then Left, Right. You should hear a loud thump sound, this is if you did it right so you must be quick with this, then go down into the bunt position & if you hit the ball, it should send it sailing 900ft or so, this should really fool your opponent.