Cuba has freed Martha Beatriz Roque,
a prominent opponent of Fidel Castro, on health grounds.
Roque was the only woman in a group of 75 dissidents arrested
The 58-year-old economist was the only woman in a group of 75 people arrested in a crackdown on dissent last year.
Ms Roque is the seventh of the group to be freed in recent weeks. She had been serving a 20-year sentence.
After her release, she pledged to work for the freedom of all political prisoners in Cuba, saying: "I will fight for them".
She was arrested in March 2003 and later convicted of conspiring with the US against Cuba.
She was found guilty - among other things - of creating a website that reported on Cuba's worsening economic situation.
A year ago Ms Roque was moved to a military hospital, and was reportedly suffering from high blood pressure and chest pains.
Six other dissidents - all of whom have health problems - have been released since early June.
She says she had no idea she was going to be released. Guards at the military hospital simply told her to pack her bags. Minutes later she was driven home, to be greeted by her surprised family.
She says she believes her release was entirely due to her failing health.
Ms Roque said that she had not accepted any conditions for her release, and paid tribute to international campaigning on her behalf.
"I thank the exile community and the international community
because I am convinced pressure on the Cuban regime has achieved this," she said.
Diplomats in Havana have said Cuba is keen to avoid the international criticism that would follow should any opponents of the regime die in jail.
Fidel Castro's communist government launched a crackdown on dissidents said to be "counter-revolutionaries" in March 2003.
The campaign prompted international condemnation.