A judge in the case set a preliminary trial date of June 10.
Zimmerman, 29, has admitted killing Martin, 17, an unarmed black teenager walking in a gated community in Sanford, Feb. 26 where Zimmerman was a neighborhood watch captain. Zimmerman said he acted in self-defense.
The case generated national headlines when Sanford police originally declined to charge Zimmerman with any crime, citing the state's controversial stand-your-ground law that allows gun carriers to use their weapons if they are in physical danger.
Prosecutor Bernie de la Rionda said he expects jury selection to be a lengthier process than the trial itself, the Orlando Sentinel reported.
Zimmerman's wife Shellie was also in court Wednesday, charged with perjury after telling a judge at Zimmerman's first bond hearing that the couple were broke. In fact, the family had been raising money online to support his defense.
Her hearing was put off until Dec. 12.