Arena Naucalpan 27th Anniversary Show

The Arena Naucalpan 27th Anniversary Show was a major annual professional wrestling event produced and scripted by the Mexican professional wrestling promotion International Wrestling Revolution Group (IWRG), which took place on December 19, 2004 in Arena Naucalpan, Naucalpan, State of Mexico, Mexico. As the name implies the show celebrated the 27th Anniversary of the construction of Arena Naucalpan, IWRG's main venue in 1977. The show is IWRG's longest-running show, predating IWRG being founded in 1996 and is the fourth oldest, still held, annual show in professional wrestling.

In the main event Japanese wrestler MAZADA faced off against the Mexican Dr. Cerebro in a Lucha de Apuestas, or "bet match", where both wrestlers put their hair on the line in the match. The match saw MAZADA defeat Dr. Cerebro, two falls to one. The show included four additional matches and featured a mixture of IWRG and Consejo Mundial de Lucha Libre (CMLL) wrestlers.