The 71-year-old tenor, who underwent surgery for pancreatic cancer last year, was brought to Modena's Polyclinic on Wednesday and was being kept under observation. Doctors were expected to release him in coming days, according to separate statements from the hospital and his manager, Terri Robson.
Pavarotti was vacationing at his holiday home in Pesaro, an Adriatic seaside resort 125 miles southeast of Modena, when his doctor noticed that he had a fever and decided to admit him to the hospital for tests, Robson said.
"He remains under observation and his condition is now stable," she said. "It is expected that the doctors will release him from hospital in the next few days."
The local daily Il Resto del Carlino reported on its Web site that Pavarotti had pneumonia. Robson declined to comment on the report in a phone interview and a subsequent e-mail exchange with The Associated Press.
Pavarotti had been preparing to leave New York in July 2006 to resume a farewell tour when doctors discovered a malignant pancreatic mass, Robson said at the time. He underwent surgery in New York, and his remaining 2006 concerts were canceled.
Pancreatic cancer is one of the most dangerous forms of the disease, although doctors said the surgery offered improved hopes for survival.
Pavarotti's wife said in a newspaper interview last month that he was reacting well to radiation therapy.
"I can now say he is doing well," Nicoletta Mantovani told Italian daily La Stampa. "He's reacting well to a fifth cycle of radiotherapy. He's fighting like a lion and he has never lost his heart, also because a family he adores is by his side."
According to Mantovani, the tenor was considering resuming the "Pavarotti and Friends" benefit concert that used to take place annually in Modena.
Robson, Pavarotti's London-based manager, said in a telephone interview in July that the opera great was teaching and working on a recording of sacred music.