The Florida Supreme Court upheld the death sentence given to Orange County resident Henry Sireci, who had been convicted of killing a car dealer in 1975.
Court records show that Sireci had stabbed his victim 55 times, then slashed his throat.
In 1976, records show a jury had recommended death by the electric chair for Sireci.
His most recent death sentence came in 1991, according to case records which show that the jury voted 11-1 in favor of his execution.
Sireci's attorney had sought to have the sentence overturned, since the jury was not unanimous.
Florida's high court, however, has limited itself to overturning only those non-unanimous sentences finalized after the year 2002.
Sireci's case was one of 10 Wednesday where the Florida Supreme Court upheld the death sentence given.
Sireci is one of Florida's longest-standing death row inmates.
According to corrections records, only four other inmates have been on Florida death row longer.