Channel 4's new deal runs from 2013 to 2016 and is for the the entire UK horseracing terrestrial rights.
It has been agreed with the Racecourse Media Group (RMG), in association with Jockey Club Racecourses, Ascot Racecourse and other independent racecourses.
It means Channel 4 will now exclusively broadcast all the biggest dates from the calendar including:
> Aintree's three-day John Smith's Grand National meeting,
> the Investec Derby Festival from Epsom Downs,
> Royal Ascot,
> the QIPCO British Champions Day.
They are added to long-established coverage of Cheltenham Festival, Newbury, York, Chester, Glorious Goodwood racecourses and the Flat Season QIPCO British Champions Series.
Jay Hunt, Channel 4's chief creative officer, said: "We are delighted Channel 4 is to become the sole destination for British horseracing after securing such iconic events as Royal Ascot, the John Smith's Grand National and the Investec Derby.
"These will sit alongside our established coverage of The Cheltenham Festival and major flat meetings such as Glorious Goodwood and the Ebor Festival and means we can extend our distinctive approach to all the crown jewels of the sport."
Jamie Aitchison, Channel 4's sports editor, said: "I am delighted Channel 4's 28-year association with racing has now arrived at the point where the industry has demonstrated such confidence in our ability to showcase its complete portfolio.
"This is an opportunity for us to work together to grow the sport, painting the full picture of both the flat and jumps seasons to attract new viewers whilst rewarding those loyal viewers we value so highly. Channel 4 fully understands the heritage and cultural importance of British racing, but also the sport's thirst for a bright future, and we relish the challenge ahead."
The BBC is facing considerable budget cutbacks, but claims it put in as competitive a bid as it could to retain the rights.
BBC director of sport Barbara Slater said: "We are of course disappointed that we have lost the rights, but we are pleased that all the races in the contract remain free to air."
