The County Monaghan trainer was well known for his celebrations in the winner’s enclosure, when he would usually make a rousing speech and lead an impromptu sing-song.
He was first diagnosed with cancer in 1995 and underwent several operations since then.
Brady was given just six months to live in 2003 after a cyst the size of a golf ball was found in his stomach.
In 2008 he had a quadruple bypass operation to unclog arteries that were up to 97 per cent blocked. He was also a diabetic and has problems with his lungs.
Yet despite all of his health problems, Brady tirelessly devoted his life to his horses and to raising money for the Shabra Charity Foundation which he established with his business partner, Rita Shah.
Brady’s first winner was Barr’s Hill at Navan in 1985. Among his best horses were Maralan, who won two Grade Two chases within the space of a week in February 2008, and Ebadiyan, successful in the Grade Three Punchestown Juvenile Hurdle in January 2009.
Both horses were ridden by John Cullen, who described Brady as a “great man”.
He said: “I’ve only just been told and it’s very sad.
“He was a great man and a great trainer of a horse. I can’t really think straight, to be honest.
“No one has a bad word to say about him.
“He did lots of work for charity and even when he was very sick the charity was the first thing on his mind.”
Brian Kavanagh, chief executive officer for HRI, said Brady added colour and joy whenever he was present on a racecourse.
He said: “I am deeply saddened to hear of the passing of Oliver.
“He was one our most colourful trainers and a favourite with all racegoers.
“He lit up many a race meeting and it was always a spectacle to see racegoers running from the stands to greet an Oliver Brady-trained winner.”