| 1980s: | 1983 1984 1985 1986 1987 1988 1989 |
| 1990s: | 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 |
| 2000s: | 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 |
| 2010s: | 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 |
| 2020s: | 2020 2021 2022 2023 2024 2025 2026 |
This page contains Sega-related events that occurred in 2004.
Events
- Sega officially merges with Sammy to become Sega Sammy Holdings.
- First entry in the Sega Superstars and Love and Berry series.