The three-year contract will see the society sponsor the club for the 2013, 2014 and 2015 seasons and is the third successive three-year sponsorship deal agreed between the mutual and Leeds Rhinos.
Leeds Building Society chief executive Peter Hill said: "We are delighted to sign up to the Rhinos for another three years. We share so many values; our passion for success, our team spirit and our commitment to the communities we serve.
"Leeds Rhinos have enjoyed their most successful period in history, with Leeds Building Society proudly on the front of the most popular shirt in rugby.
“Likewise, the Society has handled the financial crisis with great skill and tenacity, emerging stronger and with more members that at any time in our history.
"I am passionate about supporting grassroots rugby in our heartland and our Blue & Amber affinity account has already contributed over £320,000 for the development of junior rugby and supported Leeds Rhinos' excellent community programmes.
“I am proud that our affinity account has helped youth development at the club, which is demonstrated by the number of top class youngsters coming through from the academy.
"Both the Rhinos and ourselves are successful Leeds organisations, play major roles in the city and we have many customers and staff who are Rhinos supporters. This sponsorship puts us where we should be, at the heart of Leeds life."
There is no doubt that the partnership has been a success, with the Rhinos winning top honours with Leeds Building Society on their shirt, including Carnegie World Club Champions in 2008 and 2012, Grand Final winners in 2007, 2008, 2009 and 2011, and the League Leaders Shield in 2009.
Leeds Rugby chief executive Gary Hetherington said: "Leeds Building Society has certainly played a major part in our success when you consider that we have won seven major trophies in the six years they have been main sponsors, and this year's Challenge Cup and Grand Final are still to play for.
“There is a perfect fit between us both and we are very proud to carry the name of a major Leeds business on the shirts. This is an excellent deal for both parties and we are absolutely delighted.
"Over the past 12 years we have built up a very successful partnership with Leeds Building Society through our affinity account for Rhinos supporters.
“We share many common ideals. We are both proud of our heritage, are integral parts of the fabric of the city and embrace change. We both reward loyalty and offer outstanding value.”
The Rhinos are currently building up for their Carnegie Challenge Cup semi-final against the Wigan Warriors on Saturday and Hetherington added: "Our success on the pitch could not be achieved without successful partnerships off it. There is no doubt that having a main club sponsor as successful as Leeds Building Society is vitally important to us and I am sure we will have a bright future together, starting hopefully with a win on Saturday."
