The Beatles legend was gunned down by Chapman outside his New York apartment building in December, 1980, sending the pop world into mourning.
MCCartney was left devastated by his former bandmate's death, and he is adamant Chapman is the one person in the world he cannot forgive for his wrongdoing.
The Let It Be singer tells Rolling Stone magazine, "I think I could pretty much forgive anyone else, but I don't see why I'd want to forgive him. This is a guy who did something so crazy and terminal. Why should I bless him with forgiveness?"