Swiss rider Mauro Poncini died in an incident during qualifying for the Manx Grand Prix motorcycle races, organisers said in a statement on Wednesday.
The 29-year-old, an experienced competitor in the Supersport and Supertwin categories, was making his debut on the Isle of Man's Mountain Course.
Organisers said Poncini was one of two riders involved in the incident at Cruickshanks on the first lap of Tuesday's second session. The second competitor, who was not named in the statement, received minor injuries and was taken to hospital.
Although there were no fatalities at last year's Manx Grand Prix, and despite improved safety measures over the years, races on the island remain among the world's deadliest.
Including the annual TT races, Poncini was the 272nd recorded motorcycle or sidecar competitor fatality there since 1911. British Isle of Man TT rider Daniel Ingham died after a crash in qualifying last May.
