Rugova's spokesman, Muhamet Hamiti, said the president died shortly before midday in his residence in the region's capital, Pristina.
Rugova, a chain-smoker, was diagnosed with lung cancer in September 2005.
Rugova had been at the forefront of ethnic Albanian demands for independence from Serbia since the early 1990s, when he led a nonviolent movement against the policies of Slobodan Milosevic, the then president of Yugoslavia.
His death comes at a sensitive time for Kosovo, which is about to start negotiations about whether it should remain part of Serbia or become an independent state.
The province's ethnic Albanian majority wants full independence, but Serbs want Kosovo to remain part of Serbia- Montenegro, the union that replaced Yugoslavia.
The first formal UN-mediated talks between delegations from Kosovo and Serbia were due to take place on 25 January in Vienna.
However, the UN's special envoy to Kosovo, Martti Ahtisaari, has postponed the talks until February due to the official period of mourning that will now be observed in Kosovo for Rugova.
(compiled from agency reports)