Investigators say it occurred just before 1 p.m. Saturday.
Two armed men held up the Zales Outlet Store at the Philadelphia Mills Mall.
Officials say they used a sledgehammer to break open the display cases.
They got away with eight Rolex watches.
The suspects were spotted driving a newer model black Hyundai with tinted windows.
No one inside the store was injured.
If you have any information, you're asked to call police.