Local officials said there were three survivors of the crash. After a day of searching the scrub around the twisted wreckage, the death count was lowered to 57.
"Earlier we talked about 63 dead but we did a recount and this (57) is the official figure we have now," Ranulfo Marquez, a civil protection official, told local radio.
The bus went off the road on a steep stretch of highway linking Mexico City with the Gulf of Mexico port city of Veracruz.
Television pictures showed ambulance workers carrying bloodied bodies away from the wreckage, which was strewn about in pieces. The roof was upturned and almost intact.
Corpses were lined up on black plastic sheets on the floor of a makeshift morgue in the nearby town of Maltrata, and masked health workers were transferring them to coffins.
Debris was scattered after the bus
fell over a 200-meter cliff
The dead, including about 10 children, were all Mexicans on a chartered bus, which rescue services said was overloaded with passengers.
The crash could have been caused by brake failure or driver negligence, police said.