Saudi Arabia's King Abdullah will undergo back surgery.
The state news agency said the king arrived at a hospital in Riyadh on October 16.
The ruler of the conservative Islamic kingdom, who is thought to be 88, suffered a herniated disc late last year that required surgery in the United States.
Questions over King Abbullah's health has raised questions over who will succeed him.
His heir is Crown Prince Sultan. But he is in his mid-80s and has been in the United States since June seeking medical treatment.
compiled from agency reports