He had been battling a tumour and was hospitalised in Rome.
"Italian sport is in mourning," the Italian Olympic Committee CONI said of his death.
The Italian was a hugely successful athlete, the pinnacle of his career coming in 1980 when he won the 200m Olympic title in Moscow.
The previous year he had set a time of 19.72 in the 200m. It stood as a world record for 17 years until Michael Johnson broke it, and remains the European record over the distance.
After athletics he served for five years as a member of the European Parliament.