The victim, who hasn't been identified, had worked at the actor's home for about two years and was responsible for caring for the dogs, said Los Angeles Police officer Sandra Gonzalez.
Four mastiffs were seized by animal services, she said.
Police got a call at 7:15 a.m. from someone reporting a dead body at the home. Gonzalez didn't know who made the call.
The victim was found on the front lawn, she said.
Rhames, 46, who appeared in the "Mission Impossible" series of films, wasn't at home when the attack occurred, she said.