Leading Cuban dissident Guillermo Farinas told AFP Saturday he had been released after being detained 40 hours earlier, following an argument with agents guarding his home.
Farinas said he was released at around 8:15 am, in a telephone interview from his home in the central city of Santa Clara.
The police were "good, very professional," added the activist, who has gone on hunger strike about two dozen times against the regime.
The 50-year-old was detained along with two other dissidents after a meeting at his house.
"He went to talk to the patrol ... and then they had an argument and took him into custody," his mother, Alicia Hernandez, told AFP on Friday.
Elizardo Sanchez, head of the banned but tolerated Cuban Committee for Human Rights and National Reconciliation, said Farinas wanted to speak to the agents because "the laptop of one of the members of his organization had apparently gone missing."
He noted that dissidents are often arrested for several hours or days.
Farinas was last arrested on July 24 along with about 50 others at the funeral of fellow activist Oswaldo Paya, who was killed in a car accident.
Farinas won the Sakharov prize - the European parliament's top human rights award - in 2010 after his 135-day hunger strike to press for the release of political prisoners.
A former soldier and supporter of Fidel Castro's revolution, Farinas distanced himself from the regime in 1989 when he opposed the execution of general Arnaldo Ochoa, who was accused of drug trafficking.
In July, 406 dissidents were arrested, according to Sanchez's group. All opposition is illegal in Cuba and the communist government considers dissidents to be "mercenaries" in the pay of its top foe, the United States.
Cuba has been led by Raul Castro since 2006, when he assumed power from his ailing brother Fidel.