The following are known Game Genie Codes for Mega Man 3 on Nintendo Entertainment System (NES).

• AENKKAZA
  Start with 1 life
• IENKKAZA
  Start with 6 lives
• AENKKAZE
  Start with 9 lives
• AEEGXLPA
  Infinite lives
• PAOONPZA
  Start with 1 life after using a continue
• IAOONPZA
  Start with 6 lives after using a continue
• AAOONPZE
  Start with 9 lives after using a continue
• YEUKOTGA
  Mega-Jump
• ASXSTLGP
  Longer Slides
• NNKIALEE
  Speedy Slides
• GXVAAASA
  Infinite energy
• NYKGXSGK
  Faster Mega Man
• ZAKGNIPA
  Mega fast Mega Man