Mitsubishi Motors UK is pumping £2m into Bristol Rugby Club over the next five years. The team will be renamed Bristol Shoguns.
The sponsorship deal is believed to be the longest and one of the largest deals secured by an English premier league rugby side.
Bristol-born Mitsu-bishi UK managing director Jim Tyrrell said when he took over at the Cirencester-based company a year ago that one of his ambitions was to secure a high profile deal with a West Country rugby club.
“This is one of the best sponsorship deals we could have had,” said Mr Tyrrell.
Three years ago Bristol was on the verge of bankruptcy, rescued by local businessman Malcolm Pearce.
Jack Rowell, the former England coach and now managing director at Bristol, said the length of the deal would allow long-term planning to develop the club.
Mitsubishi will continue its sponsorship of Badminton Horse Trials – cancelled this year because of the foot and mouth crisis – and the MCC at Lord's.