Officials said the bust that depicts JFK wearing a coat and tie was ripped clean off its granite base at Presidio Plaza. The bust measures 1 foot, 8 inches in height. Together with the base, it stood about 6 feet tall.
A city parks employee discovered the headless pedestal and reported it Monday.
El Presidio Park is equipped with live surveillance cameras that don't record, so the theft wasn't captured on video.
The bust originally was unveiled on Nov. 22, 1964, exactly one year after Kennedy's assassination. It cost $1,000 and was paid for by the Pima County Democratic party, the Arizona Daily Star reported. The bust was removed in 1968 during construction of the new park. It was returned in 1971.
While thieves do steal bronze statues to cash in on the raw materials, it might be difficult to turn a profit on this particular piece, said Mary Ellen Wooten, public art program manager for the Tucson Pima Arts Council.
"It's difficult when you have a sculpture of somebody this recognizable," she told the Star. "You'd think somebody would be suspicious" if the thief tried to sell it to them.
Wooten speculated the person or people responsible for lifting the 35th president's bust might have wanted it for personal reasons and won't attempt to peddle it.
A police report has been made, and area metal shops have been informed.
"It's something that belongs to all of us and should be returned," Wooten said.
Pima County Democratic Party Chairman Don Jorgensen called the theft "disappointing and disrespectful." He said the party donated the sculpture to provide the people of Tucson a means to honor Kennedy's legacy.
"We sincerely hope those responsible will do the right thing and return the piece undamaged," Jorgensen said.