Pope Benedict landed in eastern Cuba for a three-day visit to showcase improving church-state relations and push for a larger church role at a time of change on the communist island.
President Raul Castro was on hand at Santiago de Cuba's seaside airport to greet the pope, who flew in from Mexico where he had denounced drug violence.
Pope Benedict will give a public mass in the Cuban capital on Wednesday morning before his departure.
President Raul Castro has used the Church as an interlocutor on issues such as political prisoners and dissidents, seeking support for his reforms to Cuba's rickety Soviet-style economy that partly involve slashing a million government jobs.
It was not yet known if the Pontiff would meet former Cuban leader Fidel Castro and Raul's older brother, or Venezuelan President Hugo Chavez who arrived in the Cuban capital over the weekend for cancer treatment.
In Mexico, Pope Benedict denounced drug violence and corruption, while in Cuba he was expected to build on improved relations with the state to get a bigger role for the Church by expanding its social programs and education courses.
But he fired an unexpected salvo on Friday when he told reporters that communism on the Caribbean island had failed and a new economic model was needed.
The Communist Party ended its ban on religious believers in 1991, but Cubans generally view John Paul's visit as the pivotal moment that led to improved Church-state relations.
The dissident movement Damas de Blanco, or Ladies in White, a group of Catholic women that campaigns for the release of political prisoners, said it had been told by Cuban authorities to keep clear of the pope's Santiago mass.
"They are going to present the pope with a facade, not with the true Cuba," said Ana Celia Rodriguez, a 42-year-old mother of three who is planning to try to attend the mass anyway.
"I really don't expect much change from the pope's visit. He'll see a Cuba that doesn't exist. My message for the pope is that he ought to see how things really are."
More than 70 of the group were detained briefly last week, fuelling expectations that the government, which views opponents as mercenaries of the United States, might clamp down to prevent public demonstrations during the pope's stay.