| Slot Machine |  Monopoly - Once Around Deluxe | 2003 | WMS Gaming, Inc. Chicago, IL, USA |
| Slot Machine | Monopoly - Own it All! | 2003 | WMS Gaming, Inc. Chicago, IL, USA |
| Slot Machine | Monsoon Money | 2003 | Konami Gaming, Inc. Las Vegas, NV, USA |
| Nintendo GameCube disc | Monster 4x4 - Masters of Metal | 2003 | Ubisoft Ent. Montreuil sous Bois, France |
| Nintendo GBA cart. | Monster Gate - Ooinaru Dungeon - Fuuin no Orb Model AGB-A6GJ-JPN(RK237-J1) | 2003 | Konami Corp. Japan |
| Medal game (video) | Monster Gate III | 2003 | Konami Corp. Japan |
| Slot Machine | Monster Keno | 2003 | IGT International Game Technologies Reno, NV, USA |
| PC/MS-Windows pack. | Monster Kuru Kuru | 2003 | CJ Internet Korea |
| Mobile game | Monster Kuru Kuru | 2003 | Mjoynet Korea |
| Slot Machine | Monster Mansion | 2003 | IGT International Game Technologies Reno, NV, USA |
| Nintendo GBA cart. | Monster Truck Madness Model AGB-BMTE-USA | 2003 | T-HQ, Inc. Toy HeadQuarters |
| Nintendo GBA cart. | Monster! Bass Fishing Model AGB-A4BP | 2003 | Ignition Ent., Ltd. |
| Bingo | Montana V | 2003 | Splin |
| Slot Machine | Moo Moo Paradise | 2003 | Create21 |
| PC/MS-Windows CD | Moorhuhn - Der Schatz des Pharao | 2003 | Ak Tronic Soft. & Services GmbH |
| PC/MS-Windows CD | Moorhuhn Kart Extra | 2003 | Ak Tronic Soft. & Services GmbH |
| Sony PlayStation CD | Moorhuhn Kart Model SLES-04122 | 2003 | Ak Tronic Soft. & Services GmbH |
| PC/MS-Windows CD | Moorhuhn X | 2003 | Ak Tronic Soft. & Services GmbH |
| Sony PlayStation CD | Moorhuhn X Model SLES-04174 | 2003 | Ak Tronic Soft. & Services GmbH |
| Nintendo GBA cart. | Mortal Kombat - Deadly Alliance Model AGB-AXDP | 2003 | Midway Home Ent. |
| Nintendo GameCube disc |  Mortal Kombat - Deadly Alliance Model DOL-GMKP-EUR | 2003 | Midway Home Ent. |
| Sony PlayStation 2 disc | Mortal Kombat - Deadly Alliance Model SLES-50717 | 2003 | Midway Home Ent. |
| Sony PlayStation 2 disc |  Mortal Kombat - Deadly Alliance Model SLUS-20423GH | 2003 | Midway Home Ent. |
| Microsoft XBOX disc | Mortal Kombat - Deadly Alliance PAL | 2003 | Midway Home Ent. |
| Nintendo GBA cart. | Mortal Kombat - Tournament Edition Model AGB-AW4E-USA | 2003 | Midway Home Ent. |
| Redemption game (video) | Most Wanted | 2003 | LAI Games Leisure & Allied Industries Singapore |
| Nintendo GBA cart. | Mother 1+2 Model AGB-A2UJ-JPN | 2003 | Nintendo Co., Ltd. Japan |
| PC/MS-Windows CD | Moto GP 2 | 2003 | T-HQ, Inc. Toy HeadQuarters |
| Sony PlayStation CD | Motocross Mania 2 Model SLES-04098 | 2003 | Take-Two Interactive |
| Sony PlayStation CD | Motocross Mania 2 Model SLUS-01531 | 2003 | Take-Two Interactive |
| Microsoft XBOX disc | MotoGP 2 | 2003 | Unknown |
| Nokia N-Gage card | MotoGP Model 0630720 | 2003 | T-HQ Wireless, Inc. |
| PC/MS-Windows CD | Motto! Himitsu Tai Ken | 2003 | Complet's |
| Slot Machine | Mountain King | 2003 | WMS Gaming, Inc. Chicago, IL, USA |
| Redemption game (mechanical) | Mr Claw | 2003 | Elaut Sint-Niklaas, Belgium |
| Slot Machine | Mr. Boss | 2003 | Subsino Co., Ltd. |
| Pachislot | Mr. Gang | 2003 | Kitac Kita Denshi Corp. Japan |
| Sony PlayStation 2 disc | Mr. Golf Model SLES-51493 | 2003 | Midas Int. Ent. |
| LeapFrog Leapster cart. | Mr. Pencil's Learn to Draw & Write | 2003 | LeapFrog |
| Arcade Video game | MT3000 MaxZilla Monster Truck Simulator | 2003 | MaxFlight Corp. |
