Raul was show on Cuban television welcoming Venezuelan President Hugo Chavez to Havana to mark Fidel Castro's 80th birthday.
While Fidel recuperated from surgery, state television showed Raul Castro, 75, appearing relaxed and smiling, in a warm embrace with the leftist Venezuelan leader who is Cuba's staunchest international ally.
No audio was heard as Raul Castro greeted Mr Chavez, who was dressed in a red shirt.
It was the first time Raul Castro was seen since his brother handed Cuba's leadership to him July 31 officially if temporarily for the first time in almost 48 years.
Venezuela's oil has helped keep Cuba's economy afloat in recent years.
Castro photos
Cuba marked Fidel Castro's 80th birthday by releasing photos of the communist leader, erasing any doubt that he made it through major surgery, though he warned Cubans to be ready for "bad news."
Fidel Castro said he was "happy" and vowed to fight for his health.
The world's longest-serving head of government had not been seen since he underwent emergency surgery and ceded power to his brother Raul, the defence chief, on July 31.
Since then, neither Castro had been seen publicly, fuelling some speculation about the president's health.
With a message reading "I feel very happy," pictures in the official government Juventud Rebelde newspaper showed the revolutionary leader apparently alert after the operation to halt gastrointestinal bleeding.
"To all of you who wished me health. I promise I will fight for it. ... The country is moving forward and will continue moving forward perfectly well," Castro added.
The Miami newspaper El Nuevo Herald has reported Castro underwent a colostomy.
Castro sounded prepared for complications. "I urge everyone to be optimistic and at the same time always prepared for any bad news there may be," he added.
Though Fidel Castro has postponed official celebrations for his 80th birthday until until December, the pictures were a pointed attempt to keep Castro center stage.
In the images, Fidel wore Cuban team colors - a red-white-and-blue tracksuit jacket - rather than his customary khaki military style uniform.
Two pictures show him speaking on the phone. Another has him holding a copy of Saturday's copy of Granma, the communist party daily, with his own picture on the front page.
Putin message
Russian President Vladimir Putin hailed Castro as one of the most "brilliant" political leaders of his era, in a special birthday message.
"In Russia, we know you well as one of the most brilliant and authoritative political men of current times," Mr Putin said in a telegram, according to the Kremlin.
The United States, Castro's arch enemy for decades did not let up in its campaign against the president for his birthday.
"The Cuban people deserve the right to choose their own government," a US State Department spokesman, Justin Higgins, said in Washington.
Castro has not been seen in public since July 26, the national holiday.