The following are known Game Genie Codes for Mega Man 4 on Nintendo Entertainment System (NES).

• AAUKZIZA
  Start with 1 life
• IAUKZIZA
  Start with 6 lives
• AAUKZIZE
  Start with 9 lives
• SZUGUAVG
  Infinite lives
• GXNPZTVG
  Infinite Energy Pods on pick-up
• AEOAIEPA
  Instant Mega Blast
• YXEAIOZO
  Longer sliding
• ZOEAIOZP
  Shorter sliding
• GEOAGPZA
  Faster sliding
• AAKEYPIE
  Mega-Jump
• GXENESOO
  Infinite weapon power
• GXVEIPSA
  Do not take any damage from enemies
• ZANKPTPA + ZEVALLPA
  Faster running speed