At least 52 people, including 13 children, died when a truck careened off a cliff in the southeastern Peru province of La Convencion killing all passengers.
"We are in mourning, so far we have 49 dead," said local Mayor Fedia Castro said on local television on Saturday. The victims include 12 children, he added.
Many people travel by truck in the region because of a shortage of buses.
In the last week, two other deadly crashes in southern Peru claimed the lives of 19 and 10 lives respectively.
In the latest accident, the truck fell into an abyss near the town of Suyucuyo and was carrying passengers who had participated in a regional party in the district of Santa Teresa, said the mayor.
According to a report by the government's National Institute of Statistics and Information, 781 people died in Peruvian traffic accidents in the first quarter of 2013.
Deadly crashes are common in the Peru, where enforcement of road safety rules are weak and poorly maintained roads meander up the Andes mountains.
The Peruvian Attorney General's Office says the main causes of such accidents are bus drivers' recklessness, excessive speed, alcohol drinking and sleepiness.