Hinckley, president of the 12 million-member Mormon church since 1995, was at an undisclosed hospital Tuesday afternoon, church spokeswoman Kim Farah said.
No other details, including which hospital and the nature of the medical procedure, were immediately available.
Hinckley, a third-generation Mormon, has worked for the church for 70 years. He is its most-traveled president, and remains active in church affairs despite his age. In December, he attended a 200th anniversary celebration in Vermont marking the birth of church founder Joseph Smith.
Presidents of the Mormon church serve for life.
Mormonism is one of the world's fastest-growing religions. The church has doubled in size every 14 or 15 years since 1950.
The architect of the church's vast public relations network, Hinckley has long worked to burnish the faith's image as a world religion far removed from its peculiar and polygamous roots.
In 2004 President Bush awarded Hinckley the Presidential Medal of Freedom, the highest civilian honor in the U.S., in a ceremony at the White House.