Having been at or near the top of the Magners League table all season Munster overtook their nearest rivals Ospreys in early January and have led from the front ever since.
Their second Celtic title was secured following Ospreys failure to claim maximum match points against Newport Gwent Dragons tonight leaving Munster unsurpassed at the top of the table going into the last two rounds of games.
The current European Champions previously took the league trophy in 2002/03.
David Jordan, Director of Celtic Rugby said "Congratulations must go to Munster for their success in winning the 2008/09 Magners League title.
"They clearly intended to claim the Magners League trophy this season following on from their success in Europe last, and from the outset they have been almost unstoppable, having won 13 of their 16 matches to date.
"Munster's success on the pitch has also been reflected off it and the re-opening of the impressive Thomond Park Stadium has brought capacity crowds to their Magners League games at that venue.
"The esteem in which their players are held has resulted in the selection of such a large contingent of Munster players in the British and Irish Lions touring party named last week.
"The winning of the Magners League title is a splendid achievement and the culmination of a strong and well coached squad throughout the campaign, the presentation of the trophy should prove to be a great occasion for players, backroom staff and fans alike."
Stephen Kent, Marketing Director, Wm Magner Ltd said, "We would like to offer our congratulations to everyone at Munster. They are deserving Magners League Champions and their success reflects the consistency and quality of rugby they have played all season.
It has been another very competitive season for the Magners League, setting the scene perfectly for the introduction of play offs, before then, we look forward to celebrating this recent success with Munster and their fans at Thomond Park on the last weekend of the season."
A formal trophy presentation will take place at Thomond Park Stadium, Limerick, following Munster's last home game of the season against Ospreys on Friday 15 May.
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