Andreotti was hospitalised last year with heart problems stemming from a respiratory infection.
At his prime, Andreotti was one of Italy's most powerful men: He helped draft the country's constitution after World War II, sat in parliament for 60 years and served as premier seven times. He remained a senator-for-life.
The Christian Democrat was accused of exchanging a "kiss of honour" with the Mafia's longtime No 1 boss and indicted in what was called "the trial of the century" in Palermo in the mid-1990s.
He denied any wrongdoing and was eventually cleared by Italy's highest court.