Prince Turki -- who was born in 1934, according to his official biography -- was a son of the kingdom's founder, King Abdul Aziz bin Saud, and a member of a formidable bloc of brothers known as the Sudairi seven, after their mother Hassa bin Ahmed al-Sudairi.
The bloc also included king Fahd and princes Sultan and Nayef, all now dead, as well as Saudi Arabia's King Salman.
Prince Turki, who was deputy minister of defense from 1968 to 1978, was to be buried later Saturday, AFP said.
King Salman is to receive condolences for three days from Saturday evening, the palace said.