The UPC was founded on 10 April 1947, at a meeting in the bar Chez Sierra in Bassa. Twelve men assisted the founding meeting, including Charles Assalé, Léonard Bouli, and Guillaume Bagal. The majority of the participants were trade unionists. In many ways UPC was a continuation of the Cameroonian Rally (RACAM).[example needed] On 11 April 1948 a Provisional Bureau was established. Bouli was elected general secretary, Bagal joint general secretary, Emmanuel Yap the treasurer and J-R Biboum the joint treasurer. The following day the statutes of UPC were deposited at the Mayor's office in Douala at 10.50 am. The group was, however, not legally registered. On April 13 UPC issued its first public declaration of intent, the "Appeal to the Cameroonians".
On May 6 another meeting was held, this time at the residence of Guillaume Bagal in Douala. The statutes and the "Appeal to the Cameroonians" were revised. A new Provisional Bureau was constituted made up of General Secretary: Étienne Libaï; Joint General Secretary: Léonard Bouli; Joint Secretary: Guillaume Bagal; General Treasurer: Emmanuel Yap; Joint Treasurer: Jacques Biboum; Members: Nkoudou Raphaël, Owona Ernest-Marie. On May 14 the revised statues were handed over to the Mayor's office in Douala. On June 9 the authorities allowed the registration of UPC, following pressure from the African Democratic Rally (RDA) and the French Communist Party (PCF).
On 17 June 17 the Provisional Bureau decided the UPC would call itself the "Cameroonian section of RDA", and that the first public function of UPC would be held on 22 June in Douala. The meeting of 22 June was held in the Salles de Fêtes d'Akwa and was attended by around 500 people. Libaï and Bouli addressed the function. Participatants included Ruben Um Nyobé, Charles Assalé, as well as traditional chiefs such as Ekwalla Essakra and Lobé-Bell. In November Ruben Um Nyobé took charge of the organization as its general secretary after a vote at a meeting of the Provisional Bureau. Before the meeting of the enlarged Provisional Bureau, Léopold Moumé-Etia had been mentioned as another possible candidate for the position, but he declined the nomination on personal grounds. At the second congress of RDA, celebrated in Treichville, Côte d'Ivoire, 1–5 January 1949, membership of the UPC in the RDA was confirmed, and Um Nyobé was elected vice-president of RDA.
On April 10, 1950 the enlarged Leading Committee holds a meeting in Dschang. During the course of the meeting a decision is taken to regard the function as the first congress of UPC. The congress lasted until April 13. A new Leading Committee was elected with President: Chief Mathias Djiomessi; General Secretary: Ruben Um Nyobé; Vice-presidents: Guillaume Bagal, Phillipe Essama Essi, Félix Moumié, Samuel Noumouwe and Treasurer: Emmanuel Yap. After the congress Charles Assalé left the movement and joined the procolonial fold. The party published the papers La Voix du Cameroun, Lumière, Étoile and Vérité.
After trying a parliamentary vote in 1952 without success, the UPC turned to the United Nations, who had the guardianship of Cameroon, to demand independence and reunification. Under the aegis of Ruben Um Nyobé, the Secretary-General, the party requested of the 4th UN General Assembly supervising committee in December 1952:
Ruben Um Nyobé proposed that for about ten years before independence there should be a program that would give Cameroons adequate training to assume responsibility for the state arising from independence.
From 1953, in the face of increased repression by the colonial power, the UPC followed the urging of Dr. Félix-Roland Moumié to move into radical political action. According to historian Bernard Droz, China provided weapons in the UPC. Seven years after its founding, in 1955 the Union of the Peoples of Cameroon controlled 460 village or neighborhood committees and 80,000 members, particularly on the coast in central, south and west Cameroon, among the Bamileke and Bassa.
After the first revolt in May 1955, suppressed by the French colonial authority at the time, the party was dissolved by a decree dated 13 July 1955, and its leaders were forced to go into exile in Kumba in the British Southern Cameroons, then in Cairo, Conakry, Accra and Beijing. On 28 January 1956 the UPC presented its position in a declaration to the international press signed by Félix-Roland Moumié (President), Ruben Um Nyobé (Secretary General) and the two Vice-Presidents, Ernest Ouandié and Abel Kingué. They called for reunification of French- and British-administered areas as an independent state.
Ruben Um Nyobé was killed in the bush on 13 September 1958. Felix Moumié would be poisoned in Geneva in October 1960, by the French secret service. The UPC continued its armed struggle until the arrest in August 1970 of Ernest Ouandié, who was shot six months later on 15 January 1971. Meanwhile, another leader of UPC, Osendé Afana, was killed in the south-east on 15 March 1966.
After a long period of hiding, the UPC officially re-surfaced in 1991 with the return to multiparty politics in Cameroon. The party held Congresses more or less unitary in 1991, 1996, 1998, 2002, 2004 and 2007. In 1997 the UPC presented an official candidate for president, Professor Henri Hogbe Nlend. He came second behind the incumbent President Paul Biya. who was reelected . Another attempt to nominate a member of UPC was made in 2004 with Dr. Samuel Mack Kit, but this nomination was rejected by the Supreme Court, ostensibly due to an incomplete application. The UPC has been elected to parliament and ministers to the government of Cameroon until 2007.