The family of Guillermo Fariñas says the Cuban dissident was arrested on his return to Cuba following an international tour during which he denounced the treatment of political prisoners in his homeland.
Fariñas's mother said that the car they were traveling in was intercepted by state security agents.
In 2010, the activist won the Sakharov Prize for freedom of thought.
The 60-year-old is a long-term campaigner for human rights.
He has gone on hunger strike dozens of times and spent years in prison in Cuba.
Fariñas was returning from a trip to Madrid, Brussels and the US, during which he spoke to fellow Cuban dissidents living in exile and addressed members of the European Parliament.
He told the European Parliament's subcommittee on human rights that "there are currently more than 1,000 political prisoners and prisoners of conscience in Cuba - some of them under-age - who are unjustly robbed of their freedom solely for openly disagreeing with the policies of the Communist Party".
"Cuba is not a paradise for social rights. That's a lie peddled by the regime which many in Europe buy into," he added.
Speaking to journalists in Tampa, Florida, in March, he referred to the street protests that rocked Cuba in July and which he said included many women and young people.
"They are not politically active, but they want a change. It's clearly a movement and it gives us hope," the Tampa Bay Times reported him as saying.
Hundreds of people were arrested following protests in July and have since been sentenced to long prison terms.
The government also cracked down on attempts to hold follow-up demonstrations.
Guillermo Fariñas was among a group of dissidents briefly detained in November ahead of an opposition rally which had been planned to demand the release of those arrested during the July protests.
The ruling Communist party banned the protests, arguing that they were a US-backed attempt at overthrowing the government.
Unauthorised public gatherings are illegal in Cuba and those who turn out to march risk being jailed.
In 2010, the activist won the Sakharov Prize for freedom of thought.
The 60-year-old is a long-term campaigner for human rights.
He has gone on hunger strike dozens of times and spent years in prison in Cuba.
Fariñas was returning from a trip to Madrid, Brussels and the US, during which he spoke to fellow Cuban dissidents living in exile and addressed members of the European Parliament.
He told the European Parliament's subcommittee on human rights that "there are currently more than 1,000 political prisoners and prisoners of conscience in Cuba - some of them under-age - who are unjustly robbed of their freedom solely for openly disagreeing with the policies of the Communist Party".
"Cuba is not a paradise for social rights. That's a lie peddled by the regime which many in Europe buy into," he added.
Speaking to journalists in Tampa, Florida, in March, he referred to the street protests that rocked Cuba in July and which he said included many women and young people.
"They are not politically active, but they want a change. It's clearly a movement and it gives us hope," the Tampa Bay Times reported him as saying.
Hundreds of people were arrested following protests in July and have since been sentenced to long prison terms.
The government also cracked down on attempts to hold follow-up demonstrations.
Guillermo Fariñas was among a group of dissidents briefly detained in November ahead of an opposition rally which had been planned to demand the release of those arrested during the July protests.
The ruling Communist party banned the protests, arguing that they were a US-backed attempt at overthrowing the government.
Unauthorised public gatherings are illegal in Cuba and those who turn out to march risk being jailed.