GAME GENIE CODES: Sonic 3 & Knuckles.

 No.  Code  Effect
   1  AWXT-CA4C  Don't lose rings when hit
   2  HXRT-AA6A  Infinite time
   3  96BA-CAG6 + 98MA-CAF0  Keep shields (fire, water, lightning) when hit
   4  AKVT-AA76+AMNA-EA24  Keep rings between levels
   5  ATGT-CA3Y  Super shoes don't run out with time
   6  RENT-C6YA  Sonic can always double jump
 (can't use water shield or become Super Sonic)
   7  RENT-C6V6  Sonic can always use Fireball Spin Dash
 (can't double jump, bounce, or become Super Sonic)
   8  RGSA-A6YY  Only 1 blue sphere needed to get a chaos emerald
   9  AANA-CNA0  Sonic jumps as high as Knuckles (slightly lower than usual)
 10  4ANA-CRA0  High jump for Sonic
 11  2ANA-CWA0  Super jump for Sonic
 12  AANA-C4A0  Mega jump for Sonic
 13  AANA-DYA0  Orbital jump for Sonic
 14  TB5T-CNCR  Knuckles jumps as high as Sonic (slightly higher than usual)
 15  PV5T-CRCR  High jump for Knuckles
 16  AB5T-CWCR  Super jump for Knuckles
 17  AB5T-C2CR  Mega jump for Knuckles
 18  AB5T-DTCR  Orbital jump for Knuckles
 19  ALNA-AACR  Rings worth 2 in special stage
 20  ARNA-AACR  Rings worth 3 in special stage
 21  AWNA-AACR  Rings worth 4 in special stage
 22  A0NA-AACR  Rings worth 5 in special stage
 23  BLNA-AACR  Rings worth 10 in special stage
 24  A2NT-CAG6  Only 6 chaos emeralds needed to become Super Sonic
 25  AYNT-CAG6  Only 5 chaos emeralds needed to become Super Sonic
 26  ATNT-CAG6  Only 4 chaos emeralds needed to become Super Sonic
 27  ANNT-CAG6  Only 3 chaos emeralds needed to become Super Sonic
 28  AJNT-CAG6  Only 2 chaos emeralds needed to become Super Sonic
 29  AENT-CAG6  Only 1 chaos emerald needed to become Super Sonic
 30  AANT-CAG6  Become Super Sonic without any chaos emeralds
 31  NTNT-CAHL  100 rings needed to become Super Sonic instead of 50
 32  FANT-CAHL  40 rings needed to become Super Sonic
 33  DENT-CAHL  25 rings needed to become Super Sonic
 34  BJNT-CAHL  10 rings needed to become Super Sonic
 35 AENT-CAHL  1 ring needed to become Super Sonic
 36  AANT-CAGY+AAPA-CAB8  Become Super-Duper Sonic without any emeralds
 (you still need 50 rings unless using one of the above codes)
 37  NTPT-CA50  Rings aren't used as Super (or Super-Duper) Sonic/Knuckles
 38  RHJA-E60L  Bonus round always activated after every checkpoint
 39  BXLA-EA5G  Bonus round is always Slot Machine
 40  A5LA-EA5G  Bonus round is always Glowing Spheres
 41  A36A-CACW  Only 6 chaos emeralds needed to become Super Knuckles
 42  AZ6A-CACW  Only 5 chaos emeralds needed to become Super Knuckles
 43  AV6A-CACW  Only 4 chaos emeralds needed to become Super Knuckles
 44  AP6A-CACW  Only 3 chaos emeralds needed to become Super Knuckles
 45  AK6A-CACW  Only 2 chaos emeralds needed to become Super Knuckles
 46  AF6A-CACW  Only 1 chaos emerald needed to become Super Knuckles
 47  AB6A-CACW  Become Super Knuckles without any chaos emeralds
 48  NV6A-CADA  100 rings needed to become Super Knuckles instead of 50
 49  FB6A-CADA  40 rings needed to become Super Knuckles
 50  DF6A-CADA  25 rings needed to become Super Knuckles
 51  BK6A-CADA  10 rings needed to become Super Knuckles
 52  AF6A-CADA  1 ring needed to become Super Knuckles
 53  AB6A-CACL+AB6A-CAHR  Become Super-Duper Knuckles without any emeralds
 (you still need 50 rings unless using one of the above codes)
 54  ACCT-CA2R  Can't drown

Download The Big Book of Game Genie Codes.