Mrs Brooks answered bail at a police station in Milton Keynes on Wednesday. The bail date related to her initial arrest by the Metropolitan Police in July last year when she was held over allegations of phone hacking and corruption.
The former editor of the News of the World and The Sun arrived at the police station at 10am and was not released until just after 5pm.
It is understood she was quizzed by detectives from Operation Elveden over alleged payments to Ministry of Defence employees.
She was initially due to answer bail last week but was arrested, along with her husband Charlie, on Tuesday of last week in relation to allegations of a cover-up.
Her bail date was subsequently pushed back, according to sources.
Mrs Brooks, 43, is one of only two suspects in the phone hacking inquiry, Operation Weeting, to be arrested on two separate occasions.
She was initially arrested on July 17 last year. Last week she and her husband along with a New International IT employee, Mark Hanna, and a man understood to be a driver for Mrs Brooks, were arrested.
The recent arrests saw Mrs Brooks and her husband held on suspicion of perverting the course of justice, an offence which carries a maximum life sentence.
It is believed that the arrests signal that the Scotland Yard operation is now turning its attention to allegations of a cover-up at Scotland Yard over the extend of phone hacking and corruption at the company.
Neville Thurlbeck, the News of the World's former chief reporter, is the only other person to be arrested twice in Operation Weeting. He too was arrested again last week over allegations that he intimidated a witness in the inquiry.
It is understood the arrest related to comments made of Mr Thurlbeck's blog.
On Mrs Brooks' appointment with officers on Wednesday, a spokesman for the Metropolitan Police said: "A 43-year-old woman returned on bail and was questioned at a police station in Buckinghamshire by officers from Operation Elveden.
"She has been rebailed to return to a London police station on a date in May pending further inquiries."
Mrs Brooks will, however, meet with officers again next month. She was bailed until April following last week's arrest.
A spokesman for Mrs Brooks refused to comment.
Several News International journalists have been arrested by the Metropolitan Police's Operation Elveden, an inquiry looking at allegations of corrupt payments made between the media and public officials.
As Well as Mrs Brooks, Andy Coulson, the former editor of the News of the World and more recently David Cameron's media chief, has been arrested. As have eleven journalists from The Sun.
Three police officers, a Ministry of Defence employee and a member of the armed forces have also been arrested.