Trainer and Grand National-winning jockey Richard Guest faces prosecution after one of his horses died.
Richard Guest: Won the Grand National in 2001
The RSPCA said it was taking action against him and two staff at his yard in County Durham, alleging they failed to provide proper veterinary care.
The charges relate to a mare named What's a Filly, which was put down last November.
In a statement Mr Guest said he denied the allegations and would "vigorously defend" his reputation.
An RSPCA spokeswoman said: "The RSPCA is prosecuting racehorse trainer Richard Guest and two members of his staff - head girl Louise Tidman and head lad Richard Dalton - for failing to provide a horse with proper veterinary attention and treatment."
Mr Guest runs a stables in Brancepeth, near Durham City.
He rode Red Marauder to win the Grand National in 2001 and has since become a successful trainer.
The Horseracing Regulatory Authority, which sets the industry rules and licences jockeys and trainers, said it examined all the horses in Mr Guest's yard after the mare died and found nothing wrong.
Mr Guest said: "The issue concerns the treatment of one horse under veterinary advice where the RSPCA take a view that it should have been dealt with differently from the advice we received.
"It is their policy that such issues should be resolved by the courts and their allegation is denied and is being vigorously defended.
"Everyone in racing knows of my passion for horses and their welfare and I am very distressed to have been caught up in the middle of this unfortunate affair."
The case is due to be heard at Durham Magistrates' Court on 28 July.