In all, Kennedy secretly recorded more than 248 hours of meetings and 12 hours of telephone conversations, the John F. Kennedy Presidential Library and Museum said Tuesday in a release.
The final 45 hours encompass meetings conducted during the three months leading up to the traumatic end of the Kennedy administration, library officials said.
"The library has been systematically reviewing and opening these secretly recorded tapes since 1993," Kennedy Library Director Tom Putnam said. "We are thrilled to have completed the process and know researchers will be fascinated with these recordings from John F. Kennedy's final days as president."
The tapes cover topics such as Vietnam, the 1964 presidential campaign, a discussion with Russian Foreign Minister Andrei Gromyko, Oval Office visits from Kennedy's children and the last recordings made before Kennedy left for Texas, where he was assassinated in Dallas on Nov. 22, 1963.
"Although on the one hand releasing the final recordings is a bittersweet milestone, on the other, we hope that the public will appreciate having the opportunity to hear these important discussions first hand," said Kennedy Library Archivist Maura Porter, who has been overseeing declassification of the recordings since 2001. "The presidential recordings are a historical treasure for those interested in truly feeling like a participant during Oval Office discussions from this time period. No other avenue can present the facts quite like listening to the players themselves."