The following are known Game Genie Codes for Mortal Kombat 3 on SEGA Genesis.

• DM2A-JA3Y
  From the Main Menu, press A or B or C twice to bring up each of the three Secret Menus.
• C5ZT-GA28
  Player 1 takes all damage
• RHZT-G6T8
  Player 2 takes all damage
• AMZT-GA5E
  Both players take no damage
• ACXT-KA62
  The first fight for player 1 is against Kano
• AGXT-KA62
  The first fight for player 1 is against Sonya
• ALXT-KA62
  The first fight for player 1 is against Jax
• ARXT-KA62
  The first fight for player 1 is against Nightwolf
• AWXT-KA62
  The first fight for player 1 is against Sub-Zero
• A0XT-KA62
  The first fight for player 1 is against Stryker
• A4XT-KA62
  The first fight for player 1 is against Sindel
• A8XT-KA62
  The first fight for player 1 is against Sektor
• BCXT-KA62
  The first fight for player 1 is against Cyrax
• BGXT-KA62
  The first fight for player 1 is against Kung Lao
• BLXT-KA62
  The first fight for player 1 is against Kabal
• BRXT-KA62
  The first fight for player 1 is against Sheeva
• BWXT-KA62
  The first fight for player 1 is against Shang Tsung
• B0XT-KA62
  The first fight for player 1 is against Liu Kang
• B4XT-KA62
  The first fight for player 1 is against Smoke
• B8XT-KA62
  The first fight for player 1 is against Motaro
• CGXT-KA62
  The first fight for player 1 is against Noob-Saibot
• HW1T-KAA4 + AC1T-JAA6
  All fights after 1st are against Kano
• HW1T-KAA4 + AG1T-JAA6
  All fights after 1st are against Sonya
• HW1T-KAA4 + AL1T-JAA6
  All fights after 1st are against Jax
• HW1T-KAA4 + AR1T-JAA6
  All fights after 1st are against Nightwolf
• HW1T-KAA4 + AW1T-JAA6
  All fights after 1st are against Sub-Zero
• HW1T-KAA4 + A01T-JAA6
  All fights after 1st are against Stryker
• HW1T-KAA4 + A41T-JAA6
  All fights after 1st are against Sindel
• HW1T-KAA4 + A81T-JAA6
  All fights after 1st are against Sektor
• HW1T-KAA4 + BC1T-JAA6
  All fights after 1st are against Cyrax
• HW1T-KAA4 + BG1T-JAA6
  All fights after 1st are against Kung Lao
• HW1T-KAA4 + BL1T-JAA6
  All fights after 1st are against Kabal
• HW1T-KAA4 + BR1T-JAA6
  All fights after 1st are against Sheeva
• HW1T-KAA4 + BW1T-JAA6
  All fights after 1st are against Shang Tsung
• HW1T-KAA4 + B01T-JAA6
  All fights after 1st are against Liu Kang
• HW1T-KAA4 + B41T-JAA6
  All fights after 1st are against Smoke
• HW1T-KAA4 + B81T-JAA6
  All fights after 1st are against Motaro
• HW1T-KAA4 + CG1T-JAA6
  All fights after 1st are against Noob-Saibot