The Bowl Championship Series (BCS) is a selection system designed to give the top two teams in the NCAA Football Bowl Subdivision (FBS) an opportunity to compete in a "national championship game". This championship is intended as a surrogate for a playoff system since the NCAA does not formally determine a champion in this category.

The BCS relies on a combination of polls and computer selection methods to determine relative team rankings, and to narrow the field to two teams to play in the BCS National Championship Game held after the other college bowl games. The winner of this game is crowned the BCS national champion, and is guaranteed at least a share of the national championship.

The system also selects matchups for the other prestigious BCS bowl games. The ten teams selected include the conference champion from each of the six BCS conferences plus four others. The BCS was created by formal agreement among six conferences, and has evolved to allow other conferences to participate to a lesser degree. It is not formally recognized by the NCAA as a collegiate championship.

It has been in place since the 1998 season, but a number of controversial selections have spurred changes in the system that continue into the present. Prior to the 2006 season eight teams competed in four BCS Bowls. The BCS replaced the Bowl Alliance (in place from 1995–1997), which followed the Bowl Coalition (in place from 1992–1994). As of the 2006–07 season, the BCS will air primarily on FOX while only the Rose Bowl will continue to be shown on ABC. FOX will continue to air 4 BCS Bowl Games (Orange Bowl, Fiesta Bowl, Sugar Bowl and BCS National Championship Game) through the 2009-2010 season. Starting with the 2010-2011 season, ESPN will start airing the games after outbidding FOX for the television rights.

History leading to creation of the BCS

Other NCAA sports determine their national champion through a post-season playoff tournament. However, these tournaments did not start until the 1930s and 1940's. College football was extremely popular decades earlier, when travel was too time-consuming and expensive to support a post-season playoff. The current bowl system began in 1902 with the East-West game in Pasadena, California. Held on New Year's Day in conjunction with the Tournament of Roses, this was an exhibition game between a highly rated team from the west coast and a team east of the Mississippi River. This was an ideal time for a post-season game, as fans could take off work or school during this holiday period to travel to the game. The game was renamed the Rose Bowl in the late 1920s due to the shape of the new stadium built in Pasadena. By the 1930s, the Cotton Bowl, Orange Bowl, and the Sugar Bowl were also held on January 1 to showcase teams from other regions of the country.

By the 1940s, college football conferences began signing contracts that tied their championship team to a particular bowl. In 1947, the Big Ten Conference and the Pacific Ten Conference (then known as the Pacific Coast Conference) agreed to commit their champions to play in the Rose Bowl every year, an agreement that continued under the BCS. This system raised the possibility that the two top-ranked teams in the final poll would not play each other in a bowl game. Indeed, the two top-ranked teams in the final regular-season AP Poll had only played each other in a bowl six times since the AP began releasing its final poll after the bowl games in 1968. Under the circumstances, it was also possible to have a split national championship.