Medvedev said he was happy with his visit when he left the island Friday evening on a flight from the beach resort of Varadero east of Havana, Cuba's Prensa Latina news agency reported.
"Everything has gone very well," Prensa Latina quoted the Russian president as telling local reporters. "We have defined what we are going to do next, we have cleared up everything regarding credits, and in Russia we will await President Raul Castro's visit."
Prensa Latina offered no details about what had been defined and cleared up, and carried no information about Medvedev's visit with ailing Fidel Castro. Cuban state television's evening news also did not report on the meeting with the older Castro.
Earlier Friday, Medvedev and Raul Castro laid a wreath at a monument to Soviet soldiers who died while serving in Cuba in the early 1960s, a symbol of Cuba's once-prominent part in the communist bloc and the history of its ties to Russia.
Wearing a gray suit instead of his traditional olive-green army uniform and clutching Medvedev's arm, Raul Castro shouted to television cameras, "It has been a magnificent visit and now he will see Fidel."
Russian officials deny that Medvedev's four-nation trip is meant to provoke the United States, but the chat with Fidel Castro capped meetings with Washington's staunchest opponents in the region.
Medvedev toured a visiting Russian warship on Thursday with Venezuelan President Hugo Chavez and earlier met with Bolivia's Evo Morales and Nicaragua's Daniel Ortega, saying Russia might participate in a socialist trade bloc founded by Chavez and Cuba.
Medvedev also signed deals with Brazil and Peru, part of an effort to strengthen Russia's political, economic and military connections across a region long dominated by U.S. influence.
"One must admit, to put it simply, we have never had a serious presence here," Medvedev told reporters.
"We visited states that no Russian leader, and no Soviet leader, ever visited. This means one thing: that attention simply was not paid to these countries," he said. "And in some ways we are only now beginning full-fledged, full-format and, I hope, mutually beneficial contacts with the leaders of these states...
"We should not be shy and fear competition. We must bravely enter the fight."