The Quiron Hospital in Barcelona said Samaranch died after being admitted with heart problems.
Samaranch headed the IOC from 1980 to 2001. He retired as the second-longest serving president in the history of the IOC. He was succeeded by current president Jacques Rogge.
Samaranch was a reserved but shrewd dealmaker whose 21-year term was marked by the unprecedented growth of the Olympics and the Salt Lake City corruption scandal.
The former Spanish diplomat was considered one of the defining presidents of the IOC for building the committee into a powerful global body and firmly establishing the Olympics as a world force.
The Samaranch era spanned political boycotts, the end of amateurism, the explosion of commercialization, a boom in the popularity of the games, the scourge of doping, and the Salt Lake crisis.
Ten IOC members resigned or were expelled for accepting improper inducements from the Salt Lake bid committee. Samaranch then pushed through a series of reforms to clean up the IOC, including a ban on member visits to bid cities.
When Samaranch came to power in 1980, the IOC was virtually bankrupt and the Olympics were battered by boycotts, terrorism and financial troubles.
When he left, the IOC's coffers were bulging from billions of dollars in commercial revenues, the boycott era was over, and the games were entrenched as the world's favorite sports festival.
Even in retirement, Samaranch remained active in Olympic circles and tried to help Madrid secure the 2012 and 2016 Games. Madrid finished third behind winner London and Paris for the 2012 Olympics, and second to Rio de Janeiro for 2016.
Despite the advancing age and medical troubles, Samaranch continued to travel to IOC meetings around the world. He looked increasingly frail in recent months. Attending the IOC session at the Winter Games in Vancouver in February, he walked with the aid of a female assistant.