Police and emergency services were scrambled to the scene after receiving an emergency call at around two o’clock.
It is not yet known whether the man jumped.
A Police Scotland spokesman said: “Police in Edinburgh received a report of concern for a man on the Scott Monument around 2pm on Thursday 11 February.
“The man was sadly pronounced dead at the scene after falling from the Monument.
“Princes Street is currently closed westbound from Waverley Bridge to the Mound.
“Local diversions are in place.”