Riverside County Animal Services Officer Jennifer Selter located the injured animal near Hole and Jones avenues in the La Sierra neighborhood.
One arrow had penetrated the opossum near his right eye and exited through the other side of his head and a second arrow had penetrated the opossum from the right to the left side of his body, officials said.
Selter rushed the opossum to the Western Riverside County/City Animal Shelter in Jurupa Valley, where the animal underwent emergency surgery.
"The animal was very alert and you could tell it was trying to remove the arrows itself," said Sgt. Cynthia Lee of Riverside County Animal Services. "The opossum was grabbing the arrow on its side. What a horrible thing to do to an animal."
It's unknown how long the opossum had been carrying the arrows through its body.
County Animal Services Director Robert Miller is asking anyone with information on who may have carried out this "sick act" to contact the department.