First Video of Fidel Castro in More Than a Year
Castro was shown in the video wearing a track suit and in an animated conversation with a group of law students from Venezuela's University of Carabobo who came to visit him at his home on Saturday.
He met with them for three hours, Cuban television, which aired the video on Sunday, said.
Castro was seen discussing global warming and telling the students "we are witnessing very, very, very grave developments, I would say grave for our very survival."
Castro, who turned 83 this month, led the Americas' only one-party communist country through nearly half of the 20th century and into the 21st before taking ill in July 2006.
The government later said he had gastrointestinal surgery.
He has not made a public appearance since then, and until recently photographs of him have showed him looking thin and frail, always dressed in a track suit.
But recent visitors have reported that Castro, who is still the chief of the Cuban Communist Party, was looking stronger and fitter.
In a photograph carried in the state-run media on Saturday, taken during a meeting with visiting Ecuadoran President Rafael Correa, Castro was standing, a touch fuller of face and in a bit more formal looking collared shirt.
The last time Cuban television aired video footage of Castro was June 18, 2008 when he was shown briefly alongside his friend and closest political ally Venezuelan President Hugo Chavez.
Chavez, who flew to Cuba earlier this month to meet with Castro, said on his return home that his ailing Communist mentor had "fully recovered" from the illness that had forced him to cede power to his brother, Raul, 78.
Chavez said he was surprised to see Castro stay up until 8:00 pm to toast with wine and eat cake to celebrate his 83rd birthday, along with his wife, children, grandchildren and Raul.
Images released on his birthday August 13 showed Castro flanked by a group of US clerics belonging to the Pastors for Peace organization that visited Cuba July 24 to August 3.
"He was standing tall and strong, looking as healthily as I hope is portrayed in the pictures," Reverend Lucius Walker, a member of the group, told AFP at the time.
According to Walker, Castro and his wife hosted the group at their home in Havana on August 2, with the former leader boasting about a long walk taken the day before and detailing his healthy new diet based on fruit and vegetables.
The Chavez government is Cuba's main ally and economic support, supplying the Caribbean island of 11 million with some 95,000 barrels of oil per day on preferential terms. About 30,000 Cuban doctors, dentists, nurses and technicians provide health care in Venezuela.