| Nintendo GBA cart. |  Kiss x Kiss Seirei Gakuen Model AGB-B2KJ-JPN | 2004 | Bandai Co., Ltd. Japan |
| Slot Machine | KISS Model 0051 | 2004 | Sigma Game, Inc. |
| PC/MS-Windows CD | Kkoma Daejang Mangchi | 2004 | Candy Global Media Korea |
| Slot Machine | Knight & Pay | 2004 | IGT International Game Technologies Reno, NV, USA |
| Slot Machine | Knight Times | 2004 | IGT International Game Technologies Reno, NV, USA |
| PC/MS-Windows CD | Knights of the Temple | 2004 | TDK Mediactive, Inc. |
| Nintendo GameCube disc | Knights of the Temple - Infernal Crusade Model DOL-GTPP-EUR | 2004 | TDK Mediactive, Inc. |
| IGS PGM cart. | Knights of Valour Superheroes Plus | 2004 | IGS Co., Ltd. International Game System |
| Slot Machine | Knights Quest | 2004 | AGI Austrian Gaming Industries Novomatic Group |
| Nintendo GBA cart. | Knights' Kingdom Model AGB-BKNE-USA | 2004 | T-HQ, Inc. Toy HeadQuarters |
| Nintendo GBA cart. | Knights' Kingdom Model AGB-BKNP | 2004 | T-HQ, Inc. Toy HeadQuarters |
| Slot Machine | Knox Knox Who's There ? | 2004 | IGT International Game Technologies Reno, NV, USA |
| MSX cart. | Kobashi Hb | 2004 | Van Dam, Vincent |
| Sony PlayStation 2 disc |  Koei Best Series: Shin Sangoku Musou Model SLPM-62568 | 2004 | KOEI Co., Ltd. Japan |
| Sony PlayStation CD | Koei Teiban Series: Daikoukai Jidai IV - Porto Estado Model SLPM-87335 | 2004 | KOEI Co., Ltd. Japan |
| Sony PlayStation CD | Koei Teiban Series: Kouryuuki Model SLPM-87350 | 2004 | KOEI Co., Ltd. Japan |
| Sony PlayStation CD | Koei Teiban: Harukanaru Toki no Naka de - Banjou Yuugi Model SLPM-87351 | 2004 | KOEI Co., Ltd. Japan |
| Sony PlayStation CD | Koei the Best: Harukanaru Toki no Naka de Model SLPM-87349 | 2004 | KOEI Co., Ltd. Japan |
| Sony PlayStation 2 disc | Koei the Best: Winning Post 5 Model SLPM-62517 | 2004 | KOEI Co., Ltd. Japan |
| PC/MS-Windows CD | Kohan II - Kings of War | 2004 | Global Star Soft. |
| Nintendo GBA cart. | Koinu to Issho 2 Model AGB-BI2J-JPN | 2004 | Culture Brain |
| Pachinko | Komao Densetsu | 2004 | Toyomaru Japan |
| Dedicated Console | Konami Collector's Series Arcade Advanced | 2004 | Majesco Sales, Inc. |
| Nintendo GBA cart. | Konjiki no Gashbell! Makai no Bookmark Model AGB-BKBJ-JPN | 2004 | Banpresto Japan |
| Nintendo GBA cart. | Konjiki no Gashbell! Unare! Yuujou no Zakeru 2 Model AGB-BGYJ-JPN | 2004 | Banpresto Japan |
| Slot Machine | Kossack Kash | 2004 | IGT International Game Technologies Reno, NV, USA |
| Pachislot | Koumont Yama | 2004 | Heiwa Japan |
| Nintendo GBA cart. | Koutetsu Teikoku from HOT-B Model AGB-BKTJ-JPN | 2004 | Starfish, Inc. Japan |
| MSX cart. | Kralizec 8K Tetris Hb | 2004 | Kralizec |
| MSX cart. | Kralizec Battle Tetris Hb | 2004 | Kralizec |
| Slot Machine | Kringle's Kash | 2004 | IGT International Game Technologies Reno, NV, USA |
| Sega Pico game | Kuma no Pooh-san - Tanoshii Tashizan - Hikizan Model HPC-6137 | 2004 | SEGA Toys |
| Nintendo GameCube disc | Kururin Squash! Model DOL-GKQJ-JPN | 2004 | Nintendo Co., Ltd. Japan |
| Pachislot | Kyojin no Hoshi II Art. 1 | 2004 | Aristocrat Technologies Co., Ltd. Tokyo, Japan |
| Pachislot | Kyojin no Hoshi II Art. 2 | 2004 | Aristocrat Technologies Co., Ltd. Tokyo, Japan |
| Pachislot | Kyojin no Hoshi II Art. 3 | 2004 | Aristocrat Technologies Co., Ltd. Tokyo, Japan |
| PC/MS-Windows CD | Kyonyuu hitoduma Kyushi - Chijoku no Kounai Cyoukyou ML | 2004 | Black Lilith |
| Slot Machine | Kyoto | 2004 | Aruze Corp. Japan |
| Slot Machine | L.A. Wheel | 2004 | IGT International Game Technologies Reno, NV, USA |
| Slot Machine | La Champagne | 2004 | MasterGames |
