Quagliarella joins Napoli
The 26-year-old was I Bianconeri's top scorer in the 2008/09 season with 13 goals.
He will play under Roberto Donadoni at Napoli, the former Italy coach who selected Quagliarella to play at UEFA EURO 2008.
"I am very happy," said Quagliarella. "This is what I wanted. "This is a dream come true. "I have always been a Napoli supporter."
Napoli endured a disappointing campaign, finishing 12th in Serie A.