Spartanburg County deputies and emergency workers found them suffering from gunshot wounds at a house in Inman, Spartanburg County Coroner Rusty Clevenger said in a statement, AP reported.
Four people died at the scene and a fifth died in surgery at the hospital, authorities said.
All five people killed appeared to be adults, weren't related to each other and were found in different parts of the home, the coroner said.
Spartanburg County deputies said they won't release any additional information on the shooting until the coroner has identified the people killed and notified their families.
Clevenger said his office is performing autopsies and trying to identify the victims on Monday.
The home where the bodies were found is about 10 miles (16 kilometers) northwest of Spartanburg.