The heart transplant pioneer collapsed in the morning as he was sitting by a swimming pool at the Coral Bay Hotel in the southwest coastal town of Paphos, said the hotel's assistant manager.
A Cypriot doctor tried to revive him with mouth-to-mouth resuscitation, but without success, the assistant manager said on condition of anonymity.
Barnard was rushed to the Paphos General Hospital, where his death was confirmed on arrival, said Cypriot Health Minister Frixos Savvides. Savvides said the cause of death was probably a heart attack but that this would verified in an autopsy to be conducted Monday.
A native of South Africa, Barnard always said he was surprised by the enormous attention he received after performing the world's first heart transplant 34 years ago.
It was "a very easy organ to transplant," he said. "There will be much greater scientific breakthroughs in medicine because the heart transplant was not a scientific breakthrough. It was a technical breakthrough."
But his globe-trotting travels suggested he liked the publicity, at least initially. He was photographed with film stars Gina Lollobrigida and Sophia Loren, wrote popular books and owned several restaurants.
Interviewed long after that Dec. 3, 1967, transplant at Groote Schuur Hospital in Cape Town, South Africa, Barnard said no other medical event was likely to get as much publicity "until somebody discovers how to transplant the brain."
But he was forced to restrict his time in the operating room because of arthritis in the hands.
Never one to dodge controversy, Barnard criticized South Africa's white-minority government for its apartheid policies as well as opponents of apartheid for not recognizing the good in his country.
He used non-white nurses to assist him in his operations - a first in South Africa, where non-whites previously were not allowed to treat white patients. He also transplanted the heart of a white woman into a black man.
Nelson Mandela, South Africa's former president, reacted to Barnard's death "with shock."
"He was one of our main achievers, a pioneer in heart transplant and he also has done very well in expressing his opinion on ... apartheid," Mandela said.
Saying his goal had always been to improve life, rather than prolong it, Barnard was also an advocate of euthanasia in some cases and wrote a book called "Good life, good death."
Barnard was born Nov. 8, 1922, one of four sons of the Rev. Adam Barnard, a Calvinist cleric who ministered to 7,000 people of mixed-race descent in Beaufort West, a dusty town 250 miles (400 kilometers) north of Cape Town.
He was strongly influenced by his mother, Maria, who played the organ in the town church to supplement her husband's meager salary.
"She drove into me and my brothers, year after ear: 'I expect you to be first - not second, or third, but first,"' Barnard later recalled.
His brother, Marius, was a member of his heart transplant team and was later elected to parliament as a member of the opposition.
Barnard studied medicine at the University of Cape Town. But his medical career was nearly aborted when he became nauseated watching an operation for the first time.
After completing his internship at Groote Schuur, he married nurse Alletta Gertruida Louw in 1948. He went into practice in Ceres, a mountain village 70 miles (112 kilometers) north of Cape Town.
In 1951, he returned to Cape Town as a senior medical officer at the city hospital and two years later was made registrar at Groote Schuur's surgery department.
He performed research surgery on dogs before going to the United States, where he was trained by the late Dr. C. Walton Lillehei of the University of Minnesota hospital, now Fairview-University Medical Center.
Barnard became a specialist cardio-thoracic surgeon at Groote Schuur and took over the University of Cape Town's cardio-thoracic surgery department in 1961.
Barnard developed a technique to correct the infant cardiac killer known as "transportation of the great vessels." By 1962 his team had developed an extremely successful artificial mitral heart valve.
In 1963 he duplicated a Soviet experiment by transplanting the head of one dog to another. His first heart graft was performed in 1963 on a dog. He then studied and performed a kidney graft.
After performing the first heart transplant in 1967, he called the hospital superintendent and said, "We have just done a heart transplant and thought you should know."
Lithuanian-born Louis Washkansky, 53, the first heart transplant recipient, died 18 days after receiving the heart of 18-year-old Denise Darvall, who had died in an auto accident.
But Barnard became an instant hero, and was seen on television throughout the world.
In May 1969, he divorced his wife, with whom he had two children - Deidre Jeanne and Andre Hendrik. He married Barbara Zoellner, a millionaire's daughter 32 years his junior, in 1970. They had several children before they divorced in 1981. His third wife, Karin, gave him another child in 1996.
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