The NCAA Men's Division I Basketball Championship is a single-elimination tournament performed each spring in the United States, featuring 68 college basketball teams, to determine the national championship of the major college basketball teams. The tournament, organized by the National Collegiate Athletic Association (NCAA), was created during 1939 by the National Association of Basketball Coaches, and was the idea of Ohio State University coach Harold Olsen.[1] Performed mostly during March, it is known informally as March Madness or the Big Dance, and has become one of the most famous annual sporting events in the United States. The NCAA has credited Bob Walsh of the Seattle Organizing Committee for starting the March Madness celebration during 1984.

The tournament teams include champions from 31 Division I conferences (which receive automatic bids), and 37 teams which are awarded at-large berths. These "at-large" teams are chosen by an NCAA selection committee, as detailed below. The 68 teams are divided into four regions and organized into a single elimination "bracket", which predetermines, when a team wins a game, which team it will face next. Each team is "seeded", or ranked, within its region. After an initial four games between eight lower-ranked teams, the tournament occurs during the course of three weekends, at pre-selected neutral sites around the United States. Lower-ranked teams are placed in the bracket against higher ranked teams. Each weekend eliminates three-fourths of the teams, from a round of 64, to a "Sweet Sixteen", to an "Elite Eight"; then to a Final Four the Final Four is usually played during the first weekend of April. These four teams, one from each region, then compete in one location for the national championship.

The tournament has been at least partially televised since 1969. Presently, the games are reported by CBS, TBS, TNT, and truTV by the trade-name NCAA March Madness. Starting in 2011, all games were available for viewing nationwide. As television coverage has grown, so too has the tournament's popularity. Presently, millions of Americans "fill out a bracket",[3] predicting winners of all 67 games.

With 11 national titles, UCLA has the record for the most NCAA Men's Division I Basketball Championships; John Wooden coached UCLA to 10 of its 11 titles. The University of Kentucky is second, with 8 national titles, while Indiana University and the University of North Carolina are tied for third with 5 national titles. Duke University ranks fifth with 4 national titles.