This has happened 23 times.
It has not yet occurred in the NCAA Men's Basketball Tournament.
Since the start of the 64/65 team field, there have been a total of 96 first round matchups. Of these, an 11 seed has beat a 6th seed 30 times.
5 times, and all have lost in the second round (4-88) first round record. Now five times, because Norfolk St (15) beat Missouri (2) in the 2012 NCAA tournament so as of March 16,2012 the 15 seed has beat the 2 seed 5 times and lost 100
In 2001, Hampton (15) upset Iowa State (2) 58-57. As of March 16th, 2012 the last times were 2012 when it occured twice in the same year. Lehigh (15) upset Duke (2) and Norfolk State (15) upset Missouri (2).
This has occured 23 times
Not sure exactly how many times, but the most recent time it happened was in 2007 when Baron Davis and the Golden State Warriors (8 seed) upset the Dallas Mavericks (1 seed with the best record in the NBA) in an incredible upset.
15 times: 1986 (2), 1987, 1988, 1989, 1990, 1991, 1992, 1995 (2), 1997, 1998, and 1999, 2005, 2006. Wake lost to Cleveland State in 2009 INCORRECT: Cleveland State was a 13 seed over a 4 seed Wake Forest in 2009
Only in the Women's tournament. It has never happened in the mens tournament. I believe that Stanford was the number one seed at the time, but I cannot remember whom upset them
Once. They went to the NCAA tournament for the first time in 2012 as a #15 seed.
It is difficult to guess to what is "1 seed" referring, but let's assume it's the NCAA final tournament. In the second round, 1 seed has a record of 118 wins and 20 losses.
16 seeded Harvard defeated 1 seed Stanford in the 1998 women's NCAA tournament. That is the only victory by a 16 seed in either the men's or women's tournament.
Only once, #15 Tuscaloosa State beat Georgetown in 1994
Yes it has happened 2 times in 1986 and 1997
Since 1985 when the NCAA Turnament expanded to 64 teams the No. 12 seed has beaten the number 5 seed 35 times. Or about 1 out of three.
UNC was a number 1 seed in the 2009 NCAA basketball tournament.
Villanova was the lowest seed to win the tournament as an 8 seed in 1985.
Four times a 15 seed has won their first round game and none of them advanced past the second round of play.
Wake Forest was a number 4 seed in the 2009 NCAA Basketball Tournament.
The University of Louisville, who was the number one overall seed in the tournament, and Western Kentucky University were the only two. Kentucky played in the NIT Tournament.