Edward Ray Killen, a Baptist minister and a low-level official of the Ku Klux Klan, was found guilty of manslaughter in June 2005 in Philadelphia, Miss., with jurors saying there was not enough evidence to convict him of murder. Killen was 80 at the time of his conviction. He was sentenced to three consecutive 20-year sentences.
The justices rejected review of his case in a one-line order without comment.
The disappearance of Andrew Goodman, 20, Michael Schwerner, 24, and James Earl Chaney, 21, on June 21, 1964, drew the attention of the national news media, and brought hundreds of searchers to look for their bodies.
Mississippi officials said the trio's disappearance was a hoax.
The bodies of the three men -- two white, one black -- were found buried on a nearby farm after the FBI paid local men for the information. The killings helped spur the civil rights movement.
The case was featured in the fictional film "Mississippi Burning" in 1988.