The jail has a 22-feet-high wall and a live power line over the top of the wall.
Kadapa Central Jail Superintendent Govindarajulu said four life convicts - Ravi, Deva, Ramachandra and Hanumanthu - escaped from the jail this evening at the time of "locking period".
He said that a construction work of a building is underway. From there these convicts collected wooden planks and made a makeshift ladder and climbed the compound wall.
"They covered the live electric wires with gunny bags and managed to cross the power line," the Superintendent said, adding the four managed to cross the wall by using their dhotis as ropes.
Following a complaint by the jail authorities, a case has been registered at the RIMS police station.
Police said search has been initiated for the four convicts.