The 74,500-seater venue is Wales' largest stadium by some distance, and it is a fitting venue for the country's first European Cup final, which will be played on June 3, 2017.
Having opened in 1999, the Millennium Stadium is home to the Welsh national rugby team and has hosted numerous major sporting events.
It was the venue for the 1999 Rugby World Cup final, and the home of the FA Cup and League Cup finals between 2001 and 2006 while Wembley Stadium was being redeveloped.
The decision to award Cardiff the hosting rights for 2017 was made at a UEFA Executive Committee meeting in Prague on Monday.