The detentions come less than a week before a visit to Cuba by Pope Francis.
Most of the activists were members of the predominantly Catholic dissident group, Ladies in White.
They walked through the streets of Havana holding up pictures of political prisoners, before they were rounded up by police.
According to Cuba's main dissident website, 14yMedio, members of Ladies in White and activists from other opposition groups were handcuffed and pushed into police cars and buses on Sunday afternoon.
A number of them were released hours later, it said.
Cuba says the protesters are financed by right-wing American groups to destabilise the government.
Cuban dissidents are planning to protest during the Pope's visit to the island, which begins on Saturday.
They have accused the Cuban Catholic Church of becoming too cosy with the government of Raul Castro and failing to speak out against human rights abuses.
"The Church should be concerned about this or any time human rights are involved. It's their duty," said Jose Daniel Ferrer, head of leading dissident group Patriotic Union of Cuba.
He told the Reuters news agency he was handcuffed and taken to a police station after Sunday's protest.
Police later dropped him off at a bus terminal, he said.
The Cuban Catholic Church says it defends the respect of human rights but cannot take up individual political causes.
Pope Francis played a key role in facilitating the historic negotiations between Cuba and the United States, which led to diplomatic relations being restored after more than five decades of hostilities.
Senior Cuban and American officials met in secrets for months at the Vatican before Presidents Barack Obama and Raul Castro surprised the world last December by announcing they had agreed to mend relations.

The Joseph Rowntree Foundation said the number of children in working families in poverty rose by 22,000 between 2003 and 2013.
Chief executive Julia Unwin said action to help pensioners was balanced by a "worrying rise" in working people struggling to "make ends meet".
The UK government said its plan for a national living wage would help people.
"Work is the best route out of poverty and employment in Wales is at record levels," a spokesman said.
A Welsh government spokesman added: "Despite recent improvements to the Welsh economy, we do, however, recognise in-work poverty is a growing issue and are working hard to support low-income households and deliver more well-paid jobs for the Welsh economy.
"We are helping more adults access full-time employment, supporting second-earners into work and are also improving people's skills to enable them to progress in the workplace."
People are classed as being in poverty if their household earns or receives less than 60% of the national average income of around Â£450 a week, adjusted for family size.

The tiny crustaceans are a naturally-occurring parasite that can cause disease and are responsible for many losses to wild and farmed fish stocks.
With resistance to chemical treatments rising, the Glasgow team has been looking at breeding resistance.
It has now come up with a new protocol to breed resistant fish and developed a mathematical model to predict outcomes.
Sea lice can cause skin lesions and increased susceptibility to infections by suppressing the host's immune system.
The parasite is estimated to cost the worldwide fish farming industry hundreds of millions of pounds a year.
Professor Michael Stear said: "Sea lice infection is a major threat to the health of farmed salmon and to the fish-farming economy.
"Our research has produced a practical tool for quantifying resistance to sea lice and shown that selection could substantially reduce the need for drug treatments.
"Selective breeding for sea lice resistance should reduce the impact of sea lice on fish health and thus greatly improve the sustainability of Atlantic salmon production."
The study outlining the Glasgow University model is published in the Royal Society journal Interface.
WWF Scotland director Lang Banks said: "There is no doubt that sea lice are a major problem for Scotland's salmon farming industry and that large amounts of chemicals are currently used to combat the problem.
"If we are to protect the wider environment, then finding ways to reduce the industry's reliance on chemicals is to be welcomed.
"However, as chemical use is only one of a number of environmental impacts from salmon farming, we need to see more farms sign up to the Aquaculture Stewardship Council's "responsible farming" labelling scheme, and pledge to operate more sustainably in all aspects of their operations."
Cuban police have detained more than 50 people who took part in a march calling on the island's communist government to release political prisoners.
[NEXT_CONCEPT]
Low pay and scarce hours are pushing working families and young people into poverty in Wales, a new report claims.
[NEXT_CONCEPT]
Researchers at Glasgow University have developed a new way to protect farmed salmon from sea lice.