The 71-year-old was flown by helicopter to the Geneva University Hospital following the accident in Scionzier, near Chamonix in the French Alps, spokesman John Kirby said in a statement.
He said Kerry had “likely suffered a leg injury” in the accident which occurred around 9:40 am (0740 GMT).
“Paramedics and a physician were on the scene with the secretary’s motorcade at the time of the accident,” Kirby said, adding that Kerry “is stable and… did not lose consciousness.”
Another State Department official, speaking on condition of anonymity, said Kerry “fell after hitting a curve”, adding that the secretary was “alert” and was having his leg X-rayed.
Kerry held talks Saturday in Geneva with his Iranian counterpart Mohammad Javad Zarif in efforts to secure a landmark nuclear deal ahead of a June 30 deadline.
The talks did not go into a second day as planned after Tehran rejected a key Western demand for site inspections.
There are heightened diplomatic moves to try to end a 12-year international standoff and put a nuclear bomb beyond Iran’s reach.
The lanky Kerry has become an instantly recognisable figure as a regular globetrotter.
During breaks from negotiations, he has often headed out of his hotel to ride his bike — which he usually brings along on his foreign missions — accompanied by a posse of security guards.
Kerry was scheduled leave late Sunday afternoon for Madrid.
Spain and the United States on Monday are to formalise an agreement under which Spain will host a permanent force of 2,200 US Marines for deployment on missions to Africa. -AFP