Police said officers were dispatched around 2:30 a.m. on reports of a problem at a home in the 1100 block of Tara Hills Drive.
Officers arriving on the scene spoke to a resident at the home who said there might be injured people inside, police said.
Police searched the home and found two people who were dead and appeared to have been killed.
Officers arrested a 25-year-old Pinole man at the scene.
Police have not released the names of the suspect or victims or disclosed any other details about the double homicide.
An investigation into the killings is ongoing. However, police said in a statement that "all indications are that this is an isolated incident."
Anyone with information about this case is urged to call Pinole police at (510) 724-8950.