The death sentence to Jadhav, 46, was confirmed by army chief Gen Qamar Javed Bajwa after the Field General Court Martial (FGCM) found him guilty of "all the charges", said the militarys media wing Inter-Services Public Relations (ISPR).
"The spy has been tried through Field General Court Martial under Pakistan Army Act and awarded death sentence," it said and added that the FGCM found Jadhav "guilty of all the charges."
According to the ISPR statement, Jadhav, a Commander in the Indian Navy, "confessed" before a Magistrate and the court that he was "tasked by RAW to plan, coordinate and organise espionage/sabotage activities aiming to destabilise and wage war against Pakistan by impeding the efforts of Law Enforcement Agencies for restoring peace in Balochistan and Karachi."
Jadhav was "arrested" on March 3 last year by Pakistani security forces in the restive Balochistan province after he reportedly entered from Iran. Pakistan has alleged that Jadhav was "a serving officer" in the Indian Navy and deputed to the Research and Analysis Wing (R&AW).
The Pakistan Army had released a "confessional video" of Jadhav after his arrest.
India has acknowledged that Jadhav served with the navy but denied he has any connection with the government. "The individual has no link with government since his premature retirement from Indian Navy," the External Affairs Ministry had said in a statement in March last year.
India had demanded Consular access to Jadhav, but Pakistan repeatedly denied Indian officials access to him.
The ISPR statement, however, said Jadhav, alias Hussein Mubarak Patel, was "provided with defending officer as per legal provisions".
Pakistan armys decision today is expected to further strain the ties between India and Pakistan. The two countries have been at loggerheads over several issues, including on Pakistans support to terrorism, since the terror attack on an Indian army base in Uri in Kashmir in September last year by Pakistan-based militants killed 18 Indian soldiers.
Ten days later, India launched "surgical strikes" against militant "launchpads" in Pakistan-occupied Kashmir.
Leading Pakistani experts viewed the announcement about Jadhavs death sentence as an unprecedented move, saying it will send a strong message to foreign countries engaging in spying activities in the country.
"Pakistan has sent a message that if somebody does such activities here, it will hand them severe punishment.
Those operating against the state will face a similar fate," Defence analyst Ikram Sehgal told Dawn newspaper.