The 2005 NCAA Division I men's basketball tournament involved 65 schools playing in single-elimination play to determine the national champion of men's NCAA Division I college basketball. It began on March 15, 2005, and ended with the championship game on April 4 at the Edward Jones Dome in St. Louis. North Carolina emerged as the national champion for a fourth time, defeating Illinois in the final 75–70. North Carolina's Sean May was named the tournament's Most Outstanding Player. It was coach Roy Williams's first national championship.