"The Cuban people cheer this correct decision of US President Barack Obama. It represents the removal of an obstacle in relations between our countries," he said in a speech closing the twice-yearly meeting of parliament.
Castro chaired the gathering, which unanimously ratified the deal between Havana and Washington yesterday, in a session largely focused on the communist island's historic renewal of ties with Washington.
The United States and Cuba made the breakthrough in their Cold War stand-off Wednesday, launching measures to ease a five-decade US trade embargo as well as a prisoner exchange. First official talks are scheduled for January.
Yesterday, US President Barack Obama insisted he shared the concerns of Cuban dissidents and human rights activist "that this is still a regime that represses it people."
"But through engagement, we have a better chance of bringing about change than we would have otherwise."
But the US president said he didn't "anticipate overnight changes.