Speaking at the contract signing in the Leinster Branch office in Donnybrook, Leinster Rugby Chief Executive Mick Dawson said: "We are delighted to announce that we are continuing our sponsorship with CCC and we are pleased to commit until 2012.
"We have a long-standing relationship with CCC and they have been important sponsors of the team throughout most of the professional era.
"It had been a challenging few weeks, not least for CCC as well as our loyal supporters whom I would like to thank for the patience and faith that they showed during this period, but Leinster are pleased that the uncertainty has been resolved and are delighted to move forward again with our partnership.
"Our new kit range for the 2009/10 season was launched in July and the innovative designs for male and female supporters, young and old, has been positively received.
"Our online store on www.leinsterrugby.ie has taken record stock orders over the summer months and we are optimistic that Leinster are entering an exciting era, both on and off the field."
Chris Stephenson, Chief Executive of Canterbury, added: "We are delighted to re-establish our strong working relationship with Leinster and we look forward to working with the club to achieve great results both on and off the pitch.
"As a global brand it is important for Canterbury to be linked with such a highly successful Irish team, and having an association with the Heineken Cup champions is true reinforcement that Canterbury is back - supplying state-of-the-art products to rugby's premium teams.
"Although the last three weeks have been a difficult time for Canterbury, the company can now look forward to a great future following the acquisition by JD Sports Fashion plc (JD).
"JD is a company with a full listing on the London Stock Exchange, with net assets at January 31, 2009 of £104m, which positions Canterbury well for future growth."