The Extraordinary Chambers in the Courts of Cambodia on Wednesday ratified the life sentence on the last alive Khmer Rouge leaders for their crimes against humanity.
It rejected the appeal against the sentence issued in 2014, Efe news reported.
The defendants are the former number two and ideologue of the communist party, Nuon Chea, 89, and the former head of the regime, Khieu Samphan, 84.
Both Chea and Samphan had denied the charges and denounced what they called factual and legal errors committed during the trial.
The court admitted several allegations and exempted the defendants from some charges, but considered them responsible for crimes committed after the Khmer Rouge took power in April 1975.