It contains many of the country's highest profile clubs. However it is not the highest level of rugby union in Scotland, as Edinburgh Rugby and Glasgow Warriors play against Irish, Welsh and Italian teams in the Magners League.
Until the 2009/10 season, the bottom two teams were relegated to the Second Division. Over the subsequent two seasons, and as part of a two-phased reconstruction announced by the Scottish Rugby Council, the league moved from a 12-team league linear structure into a 10-team league pyramid structure. From the start of the 2012/13 season promotion/relegation between the Premiership and the newly formed National League (formerly the Second Division) is determined as follows: the winner of the National League is automatically promoted replacing the bottom placed team from the Premiership with a play-off between the 9th placed Premiership team and the 2nd placed National League team to determine the second promotion place.
The underlying principles behind league reconstruction as set out by the Season Structure Working Party of the Scottish Rugby Council were (a) to shorten the season, (b) to reduce travel costs, (c) to reduce time involved for all, (d) to assist in growing the game and (e) to retain players in the game.
Thee current teams playing in the Premier League are: