The Mexican National Atómicos Championship (Campeonato Nacional Atómicos in Spanish) was a tag team championship for four man teams, or "Atómicos" as they are referred to in Lucha libre. The title is a "National title" controlled by the Comisión de Box y Lucha Libre Mexico D.F. (the Mexico City Boxing and Wrestling Commission), which regulates all matches where the title is defended. The championship was created in 1996 and was primarily defended in the Asistencia Asesoría y Administración (AAA) promotion. In early 2009 then champions Chessman and Los Psycho Circus (Killer Clown, Psycho Clown and Zombie Clown) were stripped of the title and it was subsequently declared inactive.
The title is a "National" title which means that non-Mexican citizens are prohibited from either challenging for or actually holding the championship. The championship is also an "Atómicos" championship, meaning it is restricted to four-man tag teams. As is the case for all the Mexican National titles, the championship is generally not allowed to be defended in any other type of match than a regular match.
The Mexican National Atómicos Championship was created in 1996 specifically for the AAA promotion to control. The first champions were crowned after an 8 team tournament that saw Pierroth, Jr., Villano III, Villano IV and Villano V become the inaugural champions. In late 1996 Los Villanos left AAA for Promo Azteca, vacating the championship. AAA did not crown new champions until August 1998, which were Los Vipers (Histeria, Maniaco, Mosco de la Merced and Psicosis II). The last Atómicos champions, Chessman and the Psycho Circus (Killer Clown, Psycho Clown and Zombie Clown) were stripped of the titles on January 25, 2009 by AAA Commissioner Vampiro. The title is presently inactive and unlikely to be reactivated; the storyline reason was that the team had attacked Vampiro at a previous event but the underlying reason lies in an announcement AAA made in December 2008 that they would stop recognizing titles without "AAA" in the name. Psicosis II has the most individual title reigns, with five. Los Vipers (Histeria, Maniaco, Mosco de la Merced II and Psicosis II) hold the record for most title reigns as a team, but The Black Family of Chessman, Dark Cuervo, Escoria and Dark Ozz hold the record for the most days, with 820 days for their two combined reigns. Oscar Sevilla and Los Barrio Boys (Alan, Billy Boy and Decnis) have held the title the shortest amount of time, 12 days.