50-year-old Kevin Rideout "is doing well and is being cared for by American representatives," says the Christian missionary organisation Sim International, for which he worked.
Rideout was kidnapped in October last year, outside his home in the capital, Niamey.
It is unclear which group held him captive.
Rideout had worked as a missionary in Niger for 19 years before the kidnapping, and served as a pilot for Sim International, according to The New York Times.
