The release was the third in 10 days following a meeting between Interior Minister Habib El-Adly and Bedouin elders. El-Adly promised to release only those with no security record or charges of crimes. So far 29 Bedouin have been released.
Thousands of members of nomadic Bedouin Arab tribes were detained by police in response to a series of bombings at tourist resorts in south Sinai in 2005 and 2006. Relations have grown more strained with sporadic clashes with security forces in recent months.
Authorities accuse the Bedouin of involvement in weapon and drug smuggling from Sinai to Israel and the Hamas-run Gaza Strip, and are building barriers along the Gaza border to stop the smuggling into the Palestinian enclave.
A security source said more Bedouin will be released in a fourth batch next week, but did not disclose how many, adding that those convicted of offenses such as possession of weapons and smuggling will be put on trial.
"The detainees were met with cheers by their relatives and parents. They looked happy but stunned by the sudden exit from prison," said the security source, who quoted their families as saying the detainees appeared gaunt and to have lost weight.
The Bedouin complain of neglect by the government and say tough economic conditions have led some of their kin to resort to smuggling and other activities the state considers criminal.
Among demands of the Bedouin elders is that the government investigate several policemen they say were involved in the killing of three tribesmen in 2007.
Meanwhile, two policemen accused in the death of an Egyptian activist will go on trial for torture on July 27, in a case that has drawn the attention of governments and rights groups abroad and led to protests at home.
Khaled Said, 28, died on June 6 in the port city of Alexandria. Witnesses and rights groups say two policemen dragged him out of an Internet cafe and beat him to death, while Egyptian authorities say he died choking on drugs.
The death of Said, who had posted an Internet video purportedly showing two policemen sharing the spoils of a drug bust before he died, has prompted anti-government demonstrations and raised concerns among Egypt's US and European allies.
"The Alexandria court headed by Mahmoud Talaat Muftah has set July 27 as the start of the trial of two policemen accused in the case of Khaled Said," a court statement said.
The general prosecutor charged the two men, police sergeant Awad Suleiman and policeman Mahmoud Salah, with illegally arresting and physically torturing Said, charges that carry a maximum penalty of 15 years in prison.
