The man, named as Evans Monsigrace, told doctors at a University of Miami field hospital in Port-au-Prince that he had been buried by the quake while cooking rice.
"Amazingly he got out after 27 days. It's amazing and we are proud to have him here," said doctor Dushyantha Jayaweera, the chief medical officer at the centre.
Jayaweera said his patient was stable. "Today he is alert, oriented," he said, "his prognosis is very good."
It was not immediately possible to verify Monsigrace's claim and there was no explanation for how he survived so long if he was trapped under the rubble without access to water.
Monsigrace was brought into the hospital on Monday and treated by emergency doctors, Jayaweera said.
"Yesterday around midday the patient was brought by his family. He was very emaciated and looked quite dehydrated," the doctor said.
According to the man's mother, he was discovered by people clearing debris who then alerted his brothers.
Jayaweera said Monsigrace was very confused, which was to be expected, but had no damage to his internals organs. "I think it tells us about people not giving up on their loved ones, they kept looking and kept hoping," the doctor said.
Jolie, 34, who has been a goodwill ambassador for the UN refugee agency UNHCR since early 2001, travelled to quake-shattered Port-au-Prince after visiting injured Haitian children in a hospital on Monday in neighboring Dominican Republic.
The actress, who has been on numerous UN humanitarian missions to help refugees from more than 20 countries, was due to visit a hospital and other relief sites treating hundreds of thousands of hurt and homeless Haitian quake survivors.
The Hollywood star, wearing a black jacket and aviator sunglasses, waved to reporters when she visited a UN base near Port-au-Prince airport, before she was driven away in a white UN vehicle.
Read all 1 comments