The bodies were located, following a anonymous tipoff, near Buenavista Tomatlan in western Michoacan state, the state attorney general's spokesman Alejandro Arellano said.
Drug related violence is so bad in Michoacan that residents have started forming so-called self-defense groups, arguing that the authorities are useless in fighting violence, kidnapping and extortion by a drug cartel called the Knights Templar.
This week 45 indigenous people who belonged to one such group were arrested on charges of robbery and possessing banned military-grade weapons.