Montazeri was an architect of the 1979 Islamic revolution who fell out with the present leadership and was under house arrest for some years.
"Hossein Ali Montazeri passed away in his home last night," the official IRNA news agency said in a report that did not mention his title. He lived in the holy Shi'ite Muslim city of Qom, south of Tehran.
In August, he described the clerical establishment as a "dictatorship", saying the authorities' handling of street unrest following a disputed presidential election in June "could lead to the fall of the regime".
