"Sarabjit has signed an appeal addressed jointly to the people of Pakistan and President Zardari and it will be sent to him (Zardari) for consideration," Awais Sheikh, the counsel for the Indian national, said.
Talking to PTI, Sheikh said he met Sarabjit in Kot Lakhpat Jail yesterday and presented the prisoner his book titled "Sarabjit Singh - A case of mistaken identity".
Sarabjit was convicted for alleged involvement in a string of bomb attacks in Punjab province that killed 14 people in 1990.
His mercy petitions have been rejected by the courts and former President Pervez Musharraf.
The Pakistan People's Party-led government put off Sarabjit's execution for an indefinite period in 2008.
Sarabjit's family says he is the victim of mistaken identity and had inadvertently strayed across the border in an inebriated state.