2004 (MMIV) was a leap year that started on a Thursday. In the Gregorian calendar, the year 2004 was the 2004th year in the Anno Domini or Common Era, the 4th year in the 3rd millennium and of the 21st century, and the 5th in the 2000s decade.
The year 2004 was designated the:
January
- January 2 – Paul Hopkins, American baseball player (b. 1904)
- January 2 – Etta Moten Barnett, American actress (b. 1901)
- January 2 – Lynn Cartwright, American actress (b. 1927)
- January 4 – Joan Aiken, English author (b. 1924)
- January 6 – Tug McGraw, American baseball player (b. 1944)
- January 6 – Pierre Charles, Prime Minister of Dominica (b. 1954)
- January 7 – Ingrid Thulin, Swedish actress (b. 1926)
- January 9 – Norberto Bobbio, Italian philosopher (b. 1909)
- January 9 – Yinka Dare, Nigerian Professional Basketball Player (b. 1972)
- January 11 – Mairtín Crawford, Irish poet (b. 1967)
- January 12 – Zeno Vendler, American philosopher of language (b. 1921)
- January 14 – Terje "Valfar" Bakken, Norwegian musician (b. 1978)
- January 14 – Uta Hagen, German actress (b. 1919)
- January 22 – Ann Miller, American dancer and actress (b. 1923)
- January 22 – Jack Tunney, Canadian wrestling promoter (b. 1935)
- January 25 – Miklos Feher, Hungarian footballer (b. 1979)
- January 27 – Jack Paar, American television show host (b. 1918)
- January 29 – M. M. Kaye, British writer (b. 1908)
- January 31 – Eleanor Holm, American swimmer (b. 1913)
February
- February 14 – Marco Pantani, Italian cyclist (b. 1970)
- February 17 – José López Portillo, President of Mexico (b. 1920)
- February 19 – Archibald Paton Thornton, British historian (b. 1921)
- February 21 – John Charles, Welsh footballer (b. 1931)
- February 21 – Nestor de Villa, Filipino actor (b. 1928)
- February 24 – John Randolph, American actor (b. 1915)
- February 26 – Boris Trajkovski, President of the Republic of Macedonia (b. 1956)
- February 26 – Adolf Ehrnrooth, Finnish general (b. 1905)
- February 27 – Paul Sweezy, American economist and editor (b. 1910)
- February 27 – Yoshihiko Amino, Japanese historian (b. 1928)
- February 28 – Daniel J. Boorstin, American historian and Librarian of Congress (b. 1914)
March
- March 2 – Mercedes McCambridge, American actress (b. 1918)
- March 2 – Marge Schott, American baseball team owner (b. 1928)
- March 4 – Claude Nougaro, French singer (b. 1929)
- March 4 – Stephen Sprouse, American fashion designer, artist, and photographer (b. 1953)
- March 5 – Priscilla Paris, American singer (b. 1953)
- March 7 – Paul Winfield, American actor (b. 1941)
- March 8 – Abu Abbas, founder of the Palestine Liberation Front (b. 1948)
- March 8 – Tichi Wilkerson Kassel, American film personality and publisher (b. 1926)
- March 15 – John Pople, English chemist, Nobel Prize laureate (b. 1925)
- March 20 – Juliana, Queen of the Netherlands (b. 1909)
- March 22 – Ahmed Yassin, Palestinian co-founder of Hamas (b. 1937)
- March 26 – Jan Sterling, American actress (b. 1921)
- March 29 – Peter Ustinov, English actor and director (b. 1921)
- March 30 – Alistair Cooke, English-born journalist (b. 1908)