Police officers were called to the man's home in Compton on Friday after a friend visited the property and discovered his body, the Los Angeles County Sheriff's Department (LASD) said in a statement.
It is believed that the man was involved with breeding and selling pit bulls.
There were five adult Pitbull dogs and eight puppies aged four to six months found in the backyard, along with the man's body.
Investigators believe the man was killed the previous evening, KTLA reports.
"He was feeding the dogs at which point maybe there was an altercation between some of the dogs and [they] ultimately attacked and mauled the victim," Michael Gomez, from LASD's Homicide Bureau, was quoted by the TV network as saying.
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Firefighters helped a woman climb out of the yard as the agitated dogs ran loose and attacked each other, KTLA also reported.
First responders then needed to corral the dogs into a neighbouring yard before they could safely access the man's body.
The Los Angeles County Department of Animal Care and Control (DACC) has taken all of the dogs into custody.
"The father of the dog owner is cooperating and has consented to signing over the dogs to DACC," the LASD said in a statement.
The dogs have been impounded and will be examined by a veterinarian.
While some cities in California have banned the breeding of pit bulls, Compton has not.
There are no state-wide bans on specific dog breeds in California.