The event returned in 2016 after a 30-year absence and has named Southampton-based Countess Mountbatten Hospice as its chosen charity this year.
The route sees runners start outside the Guildhall before heading through the countryside and past landmarks including St Catherine's Hill, Winchester Catherdral, and the King Alfred Statue.
Winchester MP Steve Brine officially started the race, alongside Deputy Mayor Cllr Frank Pearson. He said; "Everything about this event showed it was superbly organised and the turnout proved that. It was a terrific experience, joined as I was my children, to sound the horn and send thousands of runners on their way. It was brilliant also to see the wide range of local and national charities being supported by those taking part.
"Thank you to the organisers for asking me to do the honours today which was somethin different and a real privilege."
The marathon has been won by Richard Johnstone, who crossed the line in 1hr and 16min. The 35-year-old from Portsmouth, was competing in the event for the first time. He was cheered and applauded by spectators as he crossed the finishing line outside Winchester's historic guildhall.
Proudly displaying his medal he said: "I normally do ultra marathons and compete in this sort of event for training. My time is about what I thought it would be but I had hoped that competition from behind would push me forward. It's my first time here but I think I will do it again. Crossing the finishing line was just amazing."
Pictured; Steve by the start line cheering the runners as they set off and (below) with the Deputy Mayor, Cllr Frank Pearson.
More information ...