The following are known GameShark Codes for MLB 2003 on Sony Playstation (PS1).

• Home Team Score Modifier
  3001D495 00??
• Away Team Score Modifier
  3001D453 00??
• Infinite Outs
  800BA994 0000
• 1 Out And You Are Out
  D00BA994 0000
  800BA994 0002
• 2 Outs And You Are Out
  D00BA994 0000
  800BA994 0001
• Infinite Strikes
  800BA996 0000
• 1 Strike And You Are Out
  D00BA996 0000
  800BA996 0002
• 2 Strikes And You Are Out
  D00BA996 0000
  800BA996 0001
• Infinite Balls
  800BA998 0000
• 1 Ball And You Walk
  D00BA998 0000
  800BA998 0003
• 2 Balls And You Walk
  D00BA998 0000
  800BA998 0002
• 3 Balls And You Walk
  D00BA998 0000
  800BA998 0001