Dunaden, winner of the 2011 Melbourne Cup, has been retired after suffering an injury in training.

The horse, who ran under Sheikh Fahad's Pearl Bloodstock banner, beat Red Cadeaux by a nose to win the Melbourne Cup and returned to Australia the following year to take out the Caulfield Cup.

Trained in France by Mikel Delzangles, the eight-year-old also won the 2011 Hong Kong Vase and earned more STG5 million ($A9.13 million) prize money.

His last run was when ninth behind Gentildonna in the Dubai Sheema Classic in March.

"In winning the Melbourne Cup, Dunaden gave me the most exciting day's racing I have ever had," Sheikh Fahad said.

"He has been a dream horse to own. He has taken us all over the world from Europe to Dubai, Japan, Hong Kong and Australia and every time he tries his heart out and runs his race. He owes none of us anything.

"I would like thank Richard Gibson who trained the horse when we bought him and in whose care Dunaden would have stayed but for Richard moving to Hong Kong.

"As a result, Mikel Delzangles inherited a horse on the upgrade and he did the most wonderful job training Dunaden to win three Group Ones and to compete at the very top level all over the world for four consecutive seasons.

Delzangles described Dunaden as a life-changer.

"Dunaden will be very missed by all of us in the yard, but we are so proud of what he has achieved and very happy that he will get to stand at stud," he said.

"He always showed us that anything is possible when you have a big heart. I owe him so much, much more than just victories. He is a once-in-a-lifetime horse."

There has been no decision on where Dunaden will go to stud.