Ms Bhutto was tried in absentia by a court in the city of Rawalpindi for receiving kickbacks for awarding a contract to a Dubai-based company to import gold.
Officials say the "monopolistic" contract to ARY Gold Ltd, which was awarded in 1994, caused losses worth $10m to the national exchequer.
The prosecutor-general of the National Accountability Bureau (NAB), Raja Bashir, told the BBC that the sentence disqualified Ms Bhutto from elections scheduled for October.
Under a decree issued by President Pervez Musharraf on Saturday, Ms Bhutto and another former premier, Nawaz Sharif, are already effectively banned from assuming the office of prime minister for the third time.
'Rigged'
The Rawalpindi accountability court judge, Mansoor Ali Khan, said Ms Bhutto had been sentenced after repeatedly failing to appear before the court.
He also ordered the confiscation of all her immovable property, a legal term for property such as land and houses.
The former premier was ousted in 1996 and now lives in self-imposed exile in the United Arab Emirates.
Both she and her husband were sentenced to five years in jail in 1999 in another corruption case.
Ms Bhutto's lawyer, Babar Awan, described the latest case as "baseless" and politically motivated.
Mr Awan said it represented "pre-poll rigging" to prevent political leaders from participating in the elections.
Banned
Ms Bhutto, who heads the Pakistan People's Party, has indicated she may return to contest the elections.
But Saturday's decree prevents those who have held the office of prime minister twice in the past from being given a third term.
President Musharraf has repeatedly said he will stop the two former prime ministers from regaining any political power.
Critics say that, despite the promise of polls, President Musharraf is trying to ensure that he will retain power over any future parliament and prime minister.