The California Department of Fish and Game said the man was mauled early Sunday in his sleeping bag near the Yuba River.
The unidentified man, who was on a hiking trip, survived the attack with scratches and puncture wounds.
Authorities said the animal bit and clawed through the man's clothes and sleeping bag, then stopped and ran into the night.
Fish and game wardens verified the injuries and the attack after analyzing the man's clothing and sleeping bag. They also found mountain lion tracks and a dead domestic cat near the man's camp.
It is the 15th confirmed mountain lion attack in California since 1890.
The Associated Press contributed to this report.