Isa Nacewa, who has been a stand-out performer and double Heineken Cup winner for the province since his arrival in the summer of 2008, has signed a one-year extension to his deal until the end of the 2013/14 season.
Ireland international Kevin McLaughlin has signed a three-year deal, while there are two-year extensions for fellow internationals Isaac Boss, Gordon D'Arcy, Eoin Reddan and Rhys Ruddock.
A number of former Leinster Academy products such as Andrew Conway, David Kearney and Ian Madigan have agreed two-year extensions.
They will join forward duo Leo Auva'a and Aaron Dundon who have come up through the Ulster Bank League ranks with Old Belvedere and Seapoint/Clontarf, respectively, in recent years.
Leinster's regular captain Leo Cullen, Fionn Carr, John Cooney, Brendan Macken and Springbok prop Heinke van der Merwe have all agreed one-year deals, while Mark Flanagan and Tom Sexton have signed one-year development contracts.
In addition, Leinster have announced two-year deals with two Irish-qualified forwards who will link up with the province this summer - 25-year-old tighthead prop Michael Bent, who comes from Super 15 franchise the Hurricanes, and 24-year-old second row Tom Denton, who has signed from Leeds Carnegie.
Leinster Rugby are also delighted to announce that Season Ticket sales for the 2012/13 season have passed the 11,000 mark and are still available from www.leinsterrugby.ie.
Commenting on the new contracts, Leinster head coach Joe Schmidt said: "By swiftly concluding these deals, it enables us to plan ahead and I would like to pay tribute to all those who have assisted in the process.
"The process of recruitment can be quite drawn out, but we are delighted to announce these new extensions as well as welcoming Michael and Tom, who are two highly-rated forwards who will add to the competitiveness in our pack over the coming seasons.
"There is a welcome mix of homegrown youth and experienced players amongst this batch of renewals, while we are delighted to announce extensions for Isa (Nacewa) and Heinke (van der Merwe) who have both contributed a significant amount on and off the field of play since their arrival.
"Each of the players have expressed a real enthusiasm to be part of a competitive Leinster squad and it is testament to the hard work of the staff and players - allied with the backing of our growing band of supporters - that has helped make the environment here such a very positive one."
LEINSTER 2012/13 SQUAD:
Leo Auva'a - 2 years
Isaac Boss - 2 years
Fionn Carr - 1 year
Andrew Conway - 2 years
John Cooney - 1 year
Leo Cullen - 1 year
Gordon D'Arcy - 2 years
Aaron Dundon - 2 years
Mark Flanagan - 1 year development
David Kearney - 2 years
Brendan Macken - 1 year
Ian Madigan - 2 years
Kevin McLaughlin - 3 years
Isa Nacewa - 1 year extension
Eoin Reddan - 2 years
Rhys Ruddock - 2 years
Thomas Sexton - 1 year development
Heinke van der Merwe - 1 year
New contracts -
Michael Bent - 2 years
Tom Denton - 2 years