Police responded to a home in the 7400 block of South San Pedro Street around 1 p.m. after a neighbor called with concerns about a dog that had been tied up all day in the sun.
Officers responded and found the dog, a male pit bull-Rottweiler mix, dead.
The animal apparently had no water or shade, the Los Angeles Police Department said.
Neighbors said the dog was chained up all morning and they heard him barking more desperately as it got hotter outside.
The LAPD's animal cruelty task force is investigating.