Zimmerman made the brief statement during Friday's hearing over whether he should be released on bail while he awaits trial on second-degree murder charges.
Zimmerman told Martin's parents that he was "sorry for the loss of your son." He said he didn't know that Martin was 17 and that he was unarmed during their altercation in a central Florida neighborhood.
A judge says Zimmerman can be released on $150,000 bail as he awaits trial for the shooting death of Martin.
Circuit Judge Kenneth Lester set several conditions Friday for Zimmerman's release. He cannot have any firearms, drink alcohol or use drugs and must observe a curfew. The judge says details need to be worked out between Zimmerman's attorney and law enforcement, and that Zimmerman will not be released Friday.
The 28-year-old Zimmerman shot Martin the night of Feb. 26. He says Martin attacked him.