One competitor died and another was in critical condition after they ran into difficulty in the swimming phase of the Nautica New York City Triathlon.
New York City police said 64-year-old Michael Kudryk of Freehold, New Jersey, was pulled unconsious from the Hudson River on Sunday morning and was thought to have had a heart attack.
He was pronounced dead at a local hospital.
Police said a 40-year-old woman from Illinois, whose name was not immediately available, was in critical condition with heart attack symptoms and 26 others were taken from the water in need of first aid during the swim, which was the first phase of the race.
Race director Bill Burke said more than 3,000 competitors took part in the event, in which participants swim about a mile, bike 25 miles and run six miles.