The court acquitted three other defendants, including the man the prosecutor had claimed was the mastermind of the plot.
The works by the Norwegian artist were snatched by masked gunmen from the Munch Museum in Oslo in August 2004. They are still missing.
The Oslo District Court convicted Bjoern Hoen, 37, of planning the robbery, and sentenced him to seven years in prison. It found that Petter Tharaldsen, 34, drove the getaway car, and sentenced him to eight years in prison.
Petter Rosenvinge, 38, was also convicted and sentenced to four years.
Hoen and Tharaldsen were also ordered to pay $123 million in compensation to the City of Oslo, which owns the paintings.
It was not immediately clear whether they would appeal.
Stian Skjold, 30, whom the prosecution portrayed as the robbery's mastermind, was acquitted, as were Morten Hugo Johansen, 39, accused of providing the getaway car, and Thomas Nataas, who had been tried for receiving stolen property.
During the six-week trial, which ended April 24, the prosecution described the theft as an attack on Norwegian culture and demanded convictions. The defense said all the accused should be acquitted due to lack of evidence.