The Patriotic and Democratic Front of the Great National Union of Kampuchea () (PDFGNUK) was a Kampuchean mass organization set up by the Communist Party of Kampuchea (popularly known as the Khmer Rouge) on August 21, 1979 after the fall of Democratic Kampuchea to Vietnamese troops and the subsequent proclamation of the People's Republic of Kampuchea. It was set up as a counterpart to the Kampuchean United Front for National Salvation that had been nurtured by the Vietnamese. Its purpose was to rally anti-Vietnamese nationalists to support the Khmer Rouge, as part of an effort to legitimize the discredited Democratic Kampuchea regime. It was announced by Khieu Samphan, who was elected its provisional chairman. The PDFGNUK can be seen as an attempt to revive the goals of the similar GRUNK coalition of the early 1970s, an organization that united the Khmer Rouge and pro-Sihanouk forces opposing the Khmer Republic.