Ono received the items from the medical examiner in December 1980, when the former Beatle was gunned down in New York City at age 40.
"It was hard to include," Ono said. "And I thought it might be criticized as well."
But ultimately, Ono thought it was important to let people see the effects of gun violence.
The Lennon items are part of a new exhibit that will launch Tuesday at the Rock & Roll Hall of Fame Annex. "John Lennon: The New York Years" includes Lennon's famous New York City T-shirt, his upright piano from his Dakota apartment, and a posthumous 1981 Grammy Award for the couple's album "Double Fantasy."
"I know it's a kind of a sad and very poignant kind of paradox I think that he loved this place so much and this is where he was killed," she said in an interview after a news conference for the exhibit.
There are also letters documenting Lennon's long-fought battle against deportation in the early 1970s, both from the government and supporters. Glass cases also contain a dozen or so handwritten lyrics.
Ono says Lennon's death still haunts her nearly 30 years later: "I still get affected by it."
"If it (his death) was a slow a process we could have talked about it or something," she added, holding back tears.
The exhibit will be on display throughout 2009.