| Sega Mega Drive cart. |  World Championship Soccer II | 1994 | SEGA Enterprises, Ltd. Tokyo, Japan |
| Sega Mega Drive cart. |  World Class Leaderboard Golf Model T-79026-50 | 1992 | US Gold, Ltd. Birmingham, England 13442 |
| Sega Mega Drive cart. | World Cup Italia '90 | 1990 | SEGA Enterprises, Ltd. Tokyo, Japan |
| Sega Mega Drive cart. | World Cup Soccer Model G-4009 | 1989 | SEGA Enterprises, Ltd. Tokyo, Japan |
| Sega Mega Drive cart. | World Cup USA 94 Model 79126-50 | 1994 | US Gold, Ltd. Birmingham, England 13442 |
| Sega Mega Drive cart. |  World Heroes | 1994 | SEGA Enterprises, Ltd. Tokyo, Japan |
| Sega Mega Drive cart. | World of Illusion - Fushigi na Magic Box Model G-4080 | 1992 | SEGA Enterprises, Ltd. Tokyo, Japan |
| Sega Mega Drive cart. | World of Illusion Starring Mickey Mouse and Donald Duck | 1992 | SEGA Enterprises, Ltd. Tokyo, Japan |
| Sega Mega Drive cart. | Worms Model MK-1198-50 | 1995 | Ocean Soft., Ltd. 13156 |
| Sega Mega Drive cart. | Wrestle War Model 1206-50 | 1991 | SEGA Enterprises, Ltd. Tokyo, Japan |
| Sega Mega Drive cart. | Wrestle War Model G-4055 | 1991 | SEGA Enterprises, Ltd. Tokyo, Japan |
| Sega Mega Drive cart. | Wrestleball Model T-14043 | 1991 | NAMCOT Japan |
| Sega Mega Drive cart. | Wu Kong Wai Zhuan | 1996 | Ming China |
| Sega Mega Drive cart. | WWF Royal Rumble Model T-81196-50 | 1994 | Flying Edge |
| Sega Mega Drive cart. | WWF Super WrestleMania Model T-81086-50 | 1992 | Flying Edge |
| Sega Mega Drive cart. | X-Men 2 - Clone Wars Model 1550-50 | 1995 | SEGA Enterprises, Ltd. Tokyo, Japan |
| Sega Mega Drive cart. | X-Men 2 - Clone Wars Model FXME02SMC | 199? | SEGA OziSoft Australia |
| Sega Mega Drive cart. | X-Men Model 670-2482-50 | 1993 | SEGA Enterprises, Ltd. Tokyo, Japan |
| Sega Mega Drive cart. | X-perts | 1996 | SEGA Enterprises, Ltd. Tokyo, Japan |
| Sega Mega Drive cart. | XDR - X Dazedly Ray Model T-41013 | 1990 | Unipacc Japan |
| Sega Mega Drive cart. | Xeno Crisis Hb | 2019 | Bitmap Bureau, Ltd. England |
| Sega Mega Drive cart. | Xenon 2 - Megablast Model T-70076-50 | 1992 | Virgin Games, Ltd. UK 013715 |
| Sega Mega Drive cart. | Xiao Monv - Magic Girl | 1993 | Gamtec Taiwan |
| Sega Mega Drive cart. | Xin Qi Gai Wang Zi | 1996 | C&E Computer & Ent., Inc. Taiwan |
| Sega Mega Drive cart. | Ya Se Chuan Shuo | 1995 | Chuanpu Technologies |
| Sega Mega Drive cart. | Yi Men Ying Lie - Yang Jia Jiang | 199? | Unknown |
| Sega Mega Drive cart. | Yogi Bear's Cartoon Capers Model T-83146 | 1994 | Empire Interactive Europe, Ltd. |
| Sega Mega Drive cart. | Ys - Wanderers from Ys Model T-49063 | 1991 | Riot Japan |
| Sega Mega Drive cart. | Yu Yu Hakusho - Makyou Toitsusen Model G-4122 | 1994 | SEGA Enterprises, Ltd. Tokyo, Japan |
| Sega Mega Drive cart. | Yu Yu Hakusho - Sunset Fighters Model 048380 | 199? | Tec Toy Industria de Brinquedos S.A. Brazil |
| Sega Mega Drive cart. | Yu Yu Hakusho Gaiden Model G-5523 | 1994 | SEGA Enterprises, Ltd. Tokyo, Japan |
| Sega Mega Drive cart. | Zan - Yasha Enbukyoku Model T-32033 | 1991 | Wolf Team Japan |
| Sega Mega Drive cart. | Zero the Kamikaze Squirrel Model T-15176-50 | 1994 | SUNSOFT Kounan, Japan |
| Sega Mega Drive cart. | Zero Wing Model 670-2050-50 | 1992 | SEGA Enterprises, Ltd. Tokyo, Japan |
| Sega Mega Drive cart. | Zero Wing Model T-40023 P | 1991 | Toaplan Co., Ltd. Tokyo, Japan |
| Sega Mega Drive cart. | Zhan Qi - Chinese Battle Chess | 199? | Creaton Softech, Inc. Taiwan |
| Sega Mega Drive cart. | Zhong Guo Xiang Qi - Chinese Chess | 1992 | Realtec Corp. |
| Sega Mega Drive cart. | Zhuo Gui Da Shi - Ghost Hunter | 1994 | Shenchi Technology |
| Sega Mega Drive cart. | Zombies Model T-95086-50 | 1994 | Konami Co., Ltd. Japan |
| Sega Mega Drive cart. | Zool - Ninja on the Nth Dimensions | 1993 | Electronic Arts Home Computer Soft. UK 15839 |
