George Baker, who romped to victory in the world's oldest Classic horse race aboard Harbour Law at Town Moor 14 months ago, suffered severe head injuries in a fall on a frozen lake at St Moritz in February this year.
Baker, 35, has ridden over 1,300 winners in a career spanning 18 years - but has revealed his career is over.
In a statement issued by the Injured Jockeys Fund, Baker said: 'Whilst my recovery is going well, I have been thinking about the future and in consultation with Dr Jerry Hill at the BHA, have accepted it is not medically possible for me to come back to race-riding.
'Since my accident, my wife Nicola and family have been incredibly strong and their positivity has made it so much easier for me to get through the bad times.
'The Professional Jockeys Association, the Injured Jockeys Fund and Oaksey House have looked after me, and I'm well aware that if it wasn't for their help, I wouldn't be as far forward as I am. I would like to thank all of them so much, as well as the wider racing community for their support and incredible kindness.
'I have not decided what my future holds, but I will continue with my recovery programme and get as well as I can.
'Although I will not be able to race-ride again, I consider myself extremely fortunate to be where I am now.'