The open day is a unique opportunity to see the horses in the training establishments throughout the Lambourn Valley.
More than 25 trainers will open their yards to the public and more than 10,000 people are expected to take the opportunity to meet the horses, the trainers and to really see first hand the Lambourn racing industry.
Many yards have special exhibits and some demonstrations including horses using hydrotherapy pools.
Entry is £15 per person (children under 12 FREE) payable at all car parks.
Or £10 from 1.00pm for entry to the Afternoon Events Arena.
A 124-page souvenir programme is available from all car parks. Cost £5.