Ladbrokes have agreed with Doncaster to sponsor the St Leger for another three years.
The bookmakers will be taking their association with the world's oldest Classic up to a decade and have helped to raise the value of the 2012 total prize fund to a record £550,000.
"We have worked closely with Arena and Doncaster to rebuild the reputation of this great race," said Mike Dillon, director of media affairs at Ladbrokes.
"With horses such as the Sir Michael Stoute-trained Conduit going on to win the Breeders' Cup Turf and be voted Turf Horse of the Year in the USA, as well as triumphing in the 2009 King George VI and Queen Elizabeth Stakes, and winners from the Gosden stable and Godolphin, the top yards have supported the race magnificently and have helped the Ladbrokes St Leger return to its rightful position."
Mark Spincer, managing director at Doncaster, added: "We have a fantastic partnership with Ladbrokes and are extremely grateful for their long-term support at Doncaster racecourse.
"This latest announcement shows their dedication to the Ladbrokes St Leger and the Festival they have played a major part in enhancing and promoting over the past decade."
