The members of the People's Mujahedeen, an exiled opposition group, were seized during a raid on Camp Ashraf, a refugee base in Diyala province north of Baghdad in July that left 11 people dead, and are now mostly in ill-health.
"On the 72nd day of their hunger strike and seventh day of a dry hunger strike, 36 … hunger strikers who had been taken hostage in Iraq returned triumphantly to Camp Ashraf," said spokesman Shahriar Kia.
"Upon their arrival, they were immediately taken to Ashraf medical centre to rest and be looked after," he added.
The prisoners were arrested by Iraqi police at Camp Ashraf in a July 28-29 operation, held nearby for three days and transferred to a prison in a local town before finally being taken to a detention facility close to Baghdad.
A judge ruled three times that they must be released but officials repeatedly refused to comply, justifying the prolonged detention on the grounds that the prisoners had entered Iraq illegally.
No one from the government was available to comment on the issue, which is considered politically sensitive given Baghdad's close ties with Iran.
In September, US Ambassador Christopher Hill vowed to press the government, which the Mujahedeen say answers to Tehran, to honour assurances that Camp Ashraf residents would be treated humanely and not repatriated to Iran.
The group was founded in 1965 in opposition to the shah of Iran and subsequently fought the clerical regime that ousted him in the 1979 Islamic revolution.
About 3,500 Mujahedeen and their families have lived in Ashraf since former Iraqi dictator Saddam Hussein allowed the Iranian opposition to set up bases on his territory during his 1980-88 war with Tehran.
Following the 2003 US-led invasion of Iraq, American forces disarmed the Mujahedeen in Ashraf but placed the residents under protection.
Iraq's increasingly independent government has moved to take charge of the site.
