 | U.N. Defense Force: Earth Joker | 1993 | Visco | earthjkr | Shooter / Flying Vertical | 0.00 |
 | U.N. Squadron (US) | 1989 | Capcom | unsquad | Shooter / Flying Horizontal | 8.25 |
 | U.S. Championship V'ball (Japan) (clone of: vball) | 1988 | Technos | vball2pj | Sports / Volleyball | 0.00 |
| U.S. Championship V'ball (set 1) | 1988 | Technos | vball | Sports / Volleyball | 0.00 |
 | U.S. Classic | 1989 | Seta | usclssic | Sports / Golf | 0.00 |
 | U.S. Navy (Japan 901012) (clone of: cawing) | 1990 | Capcom | cawingj | Shooter / Flying Horizontal | 0.00 |
 | Ufo Senshi Yohko Chan (MC-8123, 317-0064) | 1988 | Sega | ufosensi | Maze / Shooter Large | 0.00 |
| Ufo Senshi Yohko Chan (not encrypted) (clone of: ufosensi) | 1988 | bootleg | ufosensb | Maze / Shooter Large | 0.00 |
 | Ultimate 11 - The SNK Football Championship / Tokuten Ou - Honoo no Libero, The | 1996 | SNK | ssideki4 | Sports / Soccer | 8.33 |
 | Ultimate Ecology (Japan 931203) (clone of: ecofghtr) | 1993 | Capcom | uecology | Shooter / Flying Horizontal | 0.00 |
 | Ultimate Mortal Kombat 3 (rev 1.0) (clone of: mk3) | 1994 | Midway | umk3r10 | Fighter / Versus | 0.00 |
| Ultimate Mortal Kombat 3 (rev 1.1) (clone of: mk3) | 1994 | Midway | umk3r11 | Fighter / Versus | 0.00 |
| Ultimate Mortal Kombat 3 (rev 1.2) (clone of: mk3) | 1994 | Midway | umk3 | Fighter / Versus | 10.00 |
 | Ultimate Tennis | 1993 | Art & Magic | ultennis | Sports / Tennis | 3.00 |
 | Ultra Balloon | 1996 | SunA | uballoon | Platform / Run Jump | 10.00 |
 | Ultra Maru-hi Mahjong (Japan) | 1993 | Apple | ultramhm | Tabletop / Mahjong *Mature* | 0.00 |
 | Ultra Tank | 1978 | Atari | ultratnk | Shooter / Versus | 6.00 |
 | Ultra Toukon Densetsu (Japan) | 1993 | Banpresto + Tsuburaya Prod. | utoukond | Fighter / 2.5D | 0.00 |
 | Ultra X Weapons / Ultra Keibitai | 1995 | Banpresto + Tsuburaya Prod. | ultrax | Shooter / Flying Vertical | 3.50 |
 | Ultraman (Japan) | 1991 | Banpresto/Bandai | ultraman | Fighter / Versus | 5.67 |
