Former Egyptian oil minister Sameh Fahmi was freed on Thursday pending a retrial on a controversial gas deal with Israel, the state-run newspaper al-Ahram reported on its website.
Fahmi had been serving a 15-year term imposed by a Cairo court for wasting public money in the deal, struck under former president Hosny Mubarak, which opponents charged had undervalued Egypt's gas exports, dpa reported.
Five former oil officials jailed for terms ranging from three to 10 years are also due to be retried after an appeal court quashed the verdicts in the case.
The Cairo Criminal Court ordered Fahmi's release as he had been in jail for longer than the maximum 18 months allowed for pre-trial detention under Egyptian law.
Egypt cancelled the gas export contract in April 2012, citing contractual violations and repeated attacks on a pipeline carrying the gas to Israel.