Luiz Inacio Lula da Silva spent more than an hour discussing "various topics" with his longtime friend, the 83-year-old Castro, who ceded power to his younger brother Raul - first temporarily, then permanently - after undergoing emergency intestinal surgery in July 2006.
The meeting was closed to international news media based in Havana, but information about it was carried in Cuban state media and by Brazil's private Agencia Estado news agency.
Fidel Castro has not been seen in public since falling seriously ill, and his exact ailment has remained a state secret, though he has appeared healthier in photos released periodically by Cuba's government.
Photographs of Wednesday's meeting released by Brazil's presidency show a beaming Castro wearing blue-and-white exercise clothing, one of a series of tracksuits that have become his trademark uniform since he has been holed up in an undisclosed location.
The gray-bearded revolutionary was thought to be in far graver health - in fact, rumors of his imminent death were frequent - the last time Silva came to see him in January 2008.
This time, Silva felt Castro looked "much different" and improved, Agencia Estado said, citing unidentified presidential aides. Raul Castro and Franklin Martins, Silva's communications minister, participated in the meeting. The pictures released by Brazil also showed Silva using a photographer's camera to take a shot of Fidel Castro and Martins.
On its nightly newscast, Cuba's state television reported the meeting but showed no images of Castro.
It said Castro and Silva discussed several matters, including the U.N. climate conference in Copenhagen. After that conference, Castro released a string of essays strongly criticizing U.S. President Barack Obama for Washington's brokering of an accord that urges - but does not require - major polluters to make deeper emissions cuts.
Also visiting Cuba was socialist Venezuelan President Hugo Chavez, another close friend and confidant of Fidel Castro. Silva, Chavez and Raul Castro had all been in the Mexican Caribbean city of Playa del Carmen on Tuesday for a Latin American and Caribbean "unity" summit.
There was no word on whether Fidel Castro met with Chavez, a frequent visitor to Cuba.
Before their meeting with Fidel Castro, Silva and Raul Castro donned guayabera dress shirts and traveled to the port city of Mariel, about 30 miles west of Havana, where Brazil's government is helping build a new port designed to handle full-size container ships.
The $600 million renovation is being split equally between Silva's government and Cuba. Brazil is Cuba's fourth-largest commercial partner, with nearly $700 million in trade between the two countries in 2008, the most current figures available.
Raul Castro became provisional president on July 31, 2006, and took over permanently two years ago Wednesday. But he played down the anniversary in comments to the news media.
Silva's comments were not the first recent indication Fidel Castro has turned the corner on his health.
During a visit to Havana in October, the director of the World Health Organization, Margaret Chan, met with him for more than two hours and said he was "wonderful" and "very dynamic."
Chan said at the time that Castro had more endurance than she did.
"I'm younger than him and I felt tired when he wasn't," she said.