Police responded to reports of a person lying on the ground next to a vehicle in the west side of the parking lot at about 9:50 a.m., police Sgt. Mike Barton said.
They found a man dead of a gunshot wound near a white compact car, with a firearm lying near his feet, Barton said.
Police are investigating the death, including the possibility that the gunshot wound was self-inflicted, he said.
Serramonte Center general manager Jennifer Duarte said the mall was open for business this afternoon.
"Our thoughts and prayers are with his family and friends," Duarte said.