The following are known GameShark Codes for MLB 2004 on Sony Playstation (PS1).

• Infinite Creation Points
  801E535C 03E7
• Away Team Score Modifier
  3001D494 00??
• Away Team Hits Modifier
  3001D495 00??
• Away Team Error Modifier
  3001D496 00??
• Home Team Score Modifier
  3001D452 00??
• Home Team Hits Modifier
  3001D453 00??
• Home Team Error Modifier
  3001D454 00??
• Infinite Outs
  800BAEB4 0000
• 1 Out And You Are Out
  D00BAEB4 0000
  800BAEB4 0002
• 2 Outs And You Are Out
  D00BAEB4 0000
  800BAEB4 0001
• Infinite Strikes
  800BAEB6 0000
• 1 Strike And You Are Out
  D00BAEB6 0000
  800BAEB6 0002
• 2 Strikes And You Are Out
  D00BAEB6 0000
  800BAEB6 0001
• Infinite Balls
  800BAEB6 0000
• 1 Ball And You Walk
  D00BAEB6 0000
  800BAEB6 0003
• 2 Balls And You Walk
  D00BAEB6 0000
  800BAEB6 0002
• 3 Balls And You Walk
  D00BAEB6 0000
  800BAEB6 0001