Nancy Reagan, who was first lady to President Ronald Reagan from 1981 to 1989, died Sunday morning at her home in Los Angeles at the age of 94, her spokesperson said.
Reagan had been living in Bel Air, Los Angeles, and had been in failing health in recent years.
Her 52-year marriage to Ronald Reagan was once described as the greatest love affair in the history of the American presidency.
When she became first lady in 1981, Reagan was criticised for an expensive renovation of the White House, but later became a much-loved figure.
President Reagan died in 2004.