The body of the young man, who has not been named in the Italian press, was discovered at around 7am by a passerby near Lungotevere dei Vallati, between Ponte Sisto and Ponte Garibaldi in the centre of the city.
It is unclear whether the man is a tourist or was living in the capital, Corriere della Sera reported.
Police are now investigating the cause of death. They suspect that he may have fallen from a parapet above the riverbank.
