In a statement released by the former editor of the News Of The World, Mrs Brooks said: "As you can imagine recent times have been tough.
"I now need to concentrate on correcting the distortions and rebutting the allegations about my record as a journalist, an editor and executive.
"My resignation makes it possible for me to have the freedom and the time to give my full cooperation to all the current and future inquiries, the police investigations and the CMS appearance."
Tom Mockridge, the chief executive of Sky Italia, has been named as her successor.
Source: Sky News