The new St Helens rugby league stadium will be named after the developer who delivered the project.
Langtree has secured the naming rights for five years but refused to say if or how much money has changed hands.
The 18,000-capacity stadium was completed in October by main contractor Barr after a 14-month build. The project manager was Arcadis UK.
John Downes, managing director at Langtree, said: "Our deal with Saints is a fitting conclusion to a project that we are delighted to have delivered. We are proud to be associated with such a prestigious and well-respected club and we hope the stadium will give Saints the platform from which their ambitions on and off the pitch can be realised. We look forward to continuing our relationship with Saints for many years to come.
"As a local business, it's great to be involved at such an exciting time for both the town and the club. Our association with the site will also continue and we look forward to bringing forward a second phase of retail and leisure development on the 14 acres of vacant land adjacent to the stadium."
Eamonn McManus, St Helens chairman, said: "Securing a naming rights deal was a big part of the new stadium plan and we're pleased to extend our relationship with Langtree.
"Langtree has done a fantastic job on the stadium and we know that once the stadium fit-out is complete that it's going to be the best arena in the country to watch rugby league.
"Everyone at the club can't wait to move in to the stadium and for our first game in January when Langtree Park will finally be filled with fans."
The stadium forms part of a long-term development scheme including a new 145,000 sq ft Tesco Extra store, the construction of housing by Taylor Wimpey on the former Knowsley Road site, and improved public space.
Saints' first game at Langtree Park takes place on 20 January 2011 when they take on Widnes in the Karalius Cup.
St Helens Council invested nearly £8m in the project which included the building of a new footbridge that links the stadium to the town centre.