One bus carrying 40 prisoners left the jail and drove to a US military base in west Baghdad, where tribal leaders awaited. The prisoners got out, kneeled, and prayed beside the bus.
Hundreds of relatives waited outside the prison since morning. US marines blocked off a highway as the first of at least six buses left.
The US military released 293 prisoners and plans to release another 475 next Friday, said Brigadier General Mark Kimmitt, the US chief military spokesman in Iraq. He said 22 prisoners, originally scheduled for release yesterday, will be released next Friday.
After more than nine months in the prison, Hussein Sami did not complain of physical abuse but said he and others were under psychological pressure, with guards shouting and insulting inmates.
Sami's family slaughtered a sheep to celebrate his release. He said he was not told why he was arrested.
His father and brother are still at Abu Ghraib, Sami said.
Former prisoner Mohammed al-Musawi said he was humiliated by guards during his 11-month incarceration.
"They forced me to take all my clothes off, and female prison guards were whispering and laughing at me," al-Musawi said.
He was arrested for allegedly participating in an attack against a US tank.
Al-Musawi said other detainees were beaten during interrogations.
"After taking some of the detainees into the interrogation rooms, they would come out with bruises and swellings," he said.
Both men spoke at the US military's Camp Thunder in west Baghdad.
The coalition periodically releases prisoners from the notorious Saddam-era jail, where abuse of prisoners by US soldiers has erupted into a major scandal and damaged the US-led coalition governing Iraq.
Meanwhile in Britain, Solider "C" last night told how colleagues beat Iraqis "for fun", in his first TV interview since making allegations of abuse.
The Territorial Army solider has been quizzed by Royal Military Police after going public with his claims. Now he has given a first hand account of prisoner abuse he says he witnessed on a posting in south Iraq.
The anonymous soldier told ITV's Tonight with Trevor McDonald: "They were beaten for fun."
"I saw prisoners being punched, slapped, kicked, pushed around. Sand bagged, zip tied. I saw them in those sand bags for hours and hours. Then water would be poured over them. I know some of them had trouble breathing."
Soldier C came forward after two colleagues made claims of abuse and produced photographs to back their claims, pictures branded fakes by defence chiefs.