David Jordan, Director of Celtic Rugby, said: "This award reflects both the hard work behind the scenes and the fact that Leinster's loyal fans are voting with their feet endorsing a brand of rugby that sees their team at the top of the Magners League.
"Across Europe only three teams - Leicester Tigers, Toulouse and Stade Francais - have better average league gates this season. Leinster's move to the RDS has obviously reaped rewards. Congratulations must go to everyone concerned with the province.
"Despite the early impact of the Rugby World Cup, the Magners League has experienced a growth in attendances across the board this season, and we anticipate building on that success going forward as our teams realise plans to upgrade their stadia."
Maurice Breen, Director of Marketing and New Markets, Wm. Magner, said: "We would like to offer our congratulations to everyone at Leinster, to achieve this accolade two years in a row is testament to the hard work that is put in off the field along with the loyalty of Leinster's fans.
"The move to the RDS has been a huge success and illustrates the hunger that exists for the brand of rugby played in the Magners League.
"Leinster's success off the pitch has mirrored results on it and we look forward to seeing another great game in front of a packed house on Saturday night as Leinster look for the win that would see them claim the Magners League trophy for the first time."
There will be a presentation of the salver for the Magners League's 'Best Supported Team' at half-time during Leinster's last home game of the season, against the Newport Gwent Dragons, this coming Saturday.