"Fidel! Fidel!" and "Hugo! Hugo!" the crowd of about 2,000 chanted as Castro, wearing his trademark green military fatigues, got out of his limousine. Chavez was by Castro's side as they entered the house amid a crush of security agents who kept bystanders back.
While Castro made no public comments, he smiled broadly and shook several hands reaching from the crowd.
Chavez told reporters the two were delighted by their tour. "Fidel invited me to come and get to know the house," he said. "For me, it's a real honor being here."
Castro, 79, first visited Argentina in 1959 after the Cuban revolution and returned this week to attend a summit that inducted Venezuela into theMercosur trade bloc, had never before visited the home of the guerrilla leader.
Guevara spent much of his childhood in central Argentina, where his family hoped a mild climate would ease the boy's severe asthma.
Guevara's family later moved to Buenos Aires, where he enrolled in medical school before launching his famous motorcycle trip around South America that inspired him to give up medicine for leftist revolution.
He was killed in 1967 while leading a guerrilla movement in Bolivia. His remains were taken three decades later to Cuba, where they are entombed under a massive monument.
On Saturday, black-uniformed police with dogs kept back the crowd, which threatened to engulf the green, brick-and-tile home — now a local attraction.
"We feel it! We feel it! Guevara is right with us!" the crowd shouted.
The house entrance bore the iconic photograph taken in 1960 by Alberto Korda of "Che" in a beret that helped converted Guevara into a guerrilla symbol.
The home is typical of many on the narrow streets of Alta Gracia, located 35 miles (50 kilometers) southwest of the city of Cordoba, where Castro, Chavez and six other Latin American presidents attended a regional trade summit Friday.
On their tour, Castro and Chavez viewed Guevara's birth certificate, handwritten letters and a vintage motorbike like the one he rode across South America.
"I'm sure Fidel will be touched because he knew Che so well," said house tour guide Lauren Gonzalez. She said not only Cubans but also admirers from around the world are drawn to the house.
"I never imagined I'd be here with these two men (Castro and Chavez) showing them the house where Che lived," said Ariel Vidoza, a childhood friend of Guevara's.
"Fidel asked me about Che and I told him about how we used to go to school together," Vidoza said. "In the afternoons, we played in this house and since I was older than him, I tried to watch over him because of his asthma problem."
Vidoza also said Guevara eschewed middle-class comforts early on: "Che didn't like the rich. He preferred to play with us, the poor ones."
Guevara launched an armed revolt in 1966 to bring communism to Bolivia after helping lead the Cuban revolution that ousted dictator Fulgencio Batista in 1959 and brought Castro to power.
Guevara waged a guerrilla insurgency for 13 months in Bolivia but was captured and executed by the Bolivian army at the age of 39. His death helped transform him into an iconic, larger-than-life figure revered by leftist movements worldwide.
But by some accounts, Guevara died complaining that Castro had cut off support for his guerrilla campaign in Bolivia.
Castro's visit came as Cuba prepares to mark the 53rd anniversary on Wednesday of the 1953 attack that Castro led on the Moncada military barracks in eastern Cuba, considered the birth of the Cuban revolution.
Ana Ledesma, a 50-year-old housewife from Alta Gracia, said the visit had caused a stir in the quiet community. "The truth is we are all surprised by Castro's visit," she said. "This has thrown the whole city into a state of shock."