Attorneys for Ferrell had argued this week that they needed more time for their expert to examine DNA evidence, and blamed prosecutors for not giving them the evidence sooner.
But Lake County Circuit Judge Jerry Lockett said Friday that the trial will begin Feb. 2 as previously planned.
"Everyone has had more than a year to get ready for this trial," Lockett said. "Let's get on with it."
The judge gave the green light for the trial to go ahead after assistant public defender Bill Lackay told the judge that his expert would have a chance to examine the evidence before trial.
The DNA evidence was found under the fingernails of one of the victims.
Ferrell is charged with bludgeoning Richard Wendorf and his companion, Naoma Ruth, to death in their Eustis home Nov. 25, 1996.
After the murders, the couple's daughter, Heather, 16, ran away from home with Ferrell and three other youths from Kentucky, who claimed they were members of a vampire cult. Cult members reportedly drank each others' blood and played fantasy games involving witchcraft and black magic.
Heather Wendorf claimed she didn't know her parents would be harmed, and a grand jury cleared her in the murders.
Howard Scott Anderson, 17, of Mayfield, Ky.; Dana L. Cooper, 20, and Charity Keesee, 17, both of Murray, Ky., are charged with being principals to murder. They are to be tried later in the year.