An agreement was signed by representatives of Oslo's Kon-Tiki Museum and officials of Chile's culture ministry at a ceremony in Santiago as part of a state visit by Norway's King Harald V and Queen Sonja.
The museum pieces include carved artifacts and human bones from the Rapa-Nui, the first inhabitants of the remote Chilean island in the Pacific.
"Our common interest is that the objects are returned and, above all, delivered to a well-equipped museum," said the museum's director Martin Biehl.
He warned however that the repatriation process "will take time."
Heyerdahl's family said he had long wanted to return the pieces he collected in expeditions in the mid-1950s and mid-1980s, currently exhibited in the Oslo museum.
The signing ceremony was also attended by Thor Heyerdahl Jr. who accompanied his father on one of his expeditions to the island in 1955, when he was 17.
"The repatriation is a fulfillment of my father's promise to the Rapa-Nui authorities, that the objects would be returned after they had been analyzed and published," he said.
Anthropologist and adventurer Heyerdahl became famous in 1947 when he and a crew of five crossed much of the Pacific on a reed raft, the Kon-Tiki. He was seeking to prove his theory that the Polynesian islands could have
been settled by prehistoric South American people, and not by settlers from Asia as most scholars believed. Heyerdahl died in 2002 aged 87.
"The study of human remains -- using DNA -- could demonstrate a prehistoric contact between Rapa-Nui and South America, which was the main thesis of my father," Thor Heyerdahl Jr. said.
"As a ministry we have the mission to respond to the just demand of the Rapa-Nui people to recover their cultural heritage," Chile's Culture Minister Consuelo Valdes said in a statement.
"Today, one more step has been taken through this historic agreement with Norway, which will enable the return of valuable cultural and symbolic pieces."
The Rapa Nui island community is also demanding the British government return the Hoa Hakananai, one of the most spiritually important of the island's stone monoliths, or maois, from the British Museum. The maoi was stolen from the island in 1868 by the captain of a British frigate and given to Queen Victoria.