From the start of the new rugby season, the competition formerly known as the Magners League will become the RaboDirect PRO12.
Commenting on the new four-year sponsorship deal, John Feehan, Chief Executive of RaboDirect PRO12, said: "We are delighted to welcome RaboDirect as our new title sponsor alongside our new brand PRO12.
"Securing the support of an international business with the reputation of the Rabobank Group will raise the profile of the RaboDirect PRO12 and enhance the investment in the competition.
"The Rabobank Group are active and engaged sponsors of a number of sporting properties worldwide, including Holland, Italy and Australia and we look forward to working with them.
"We are very excited to welcome RaboDirect as our new sponsor at a time when we are launching our new brand.
"Our competition has experienced a huge growth over the last few years and it was time to move it to the next level. Our new brand, the PRO12, encapsulates the structure, growth and energy of our competition.
"We look forward to working with RaboDirect, developing and nurturing the RaboDirect PRO12 competition for many years to come."
Roel van Veggel, General Manager of RaboDirect in Ireland, said: "We're absolutely delighted to be embarking on this high profile sponsorship deal. Rabobank Group, throughout its 100-year history, has always sought to put down firm roots in the communities where it operates.
"At RaboDirect we believe that our values of passion, honesty, commitment and responsibility echo the values of this professional competition and so we're very confident that we've achieved an exceptional fit in securing this sponsorship.
"We're very excited about getting involved in a sport that ignites so much passion not only in Ireland, but in communities in the UK and Italy.
"Rabobank Group's expertise in executing sponsorships globally will allow RaboDirect to take this competition to even greater heights.
"We're looking forward to generating more enthusiasm for the competition, connecting with an even larger audience of people through their love of rugby, strengthening our ties with local communities and demonstrating RaboDirect's firm commitment to our customers, most especially in the Irish market where the competition has become most popular in the last number of years."
Charlie McEwen, Sales and Marketing Director at RaboDirect PRO12, said: "Our partnership with RaboDirect marks the start of an exciting journey as we plan to build on the growth that the competition has experienced in the last five years.
"We look forward to working with RaboDirect, using their considerable International experience, to amplify the success we have had in continually improving the competition for all supporters."