More than half the population of Congo is Christian. About three-quarters of those are Roman Catholic, and a quarter are Protestant. Most of the remaining inhabitants follow traditional beliefs or belong to syncretic sects (churches that blend Christian and traditional practices). Religious minorities include Muslims and Jews.

 Christian missionaries were extremely active in Congo. Both Catholic and Protestant organizations have strongly influenced the nation's development, especially in health care and education. Before independence, there were more than 7,000 missionaries in Congo, and two universities run by church organizations. Many missionaries fled or were killed during the civil war in the 1960s, and the churches have since been largely Africanized.

Although freedom of religion was guaranteed under the 1967 constitution, relations between church and state were strained when President Mobutu launched his authenticity program, which promoted a return to African roots. Religious instruction was banned in schools, Christian names were replaced by African ones, church schools were nationalized, and religious holidays were secularized.

 In the early 1970s, new national laws officially recognized the Roman Catholic Church, the Protestant Church of Christ, the Kimbanguist Church, the Greek Orthodox Church, and the Muslim and Jewish faiths. By the end of the 1970s, many of Mobutu's anti-Christian rulings had been relaxed. Pope John Paul II visited the country in 1980 as a sign of reconciliation between Congo and the Christian church.

Syncretic churches arose in the 1920s and 1930s. Kimbanguism, an independent movement that began in 1921, inspired by the preaching of Simon Kimbangu, encouraged a return to authentic African traditions. Two other African Christian movements are Jamaa and Kitawala.

 Each ethnic group in Congo has its own traditional religion. Indigenous beliefs emphasize continuity between people and nature. Natural objects are believed to have souls. Those who hold these beliefs accept the existence of a supreme being, or god of all gods, known by Congolese as Nzambe 'a mphunngu. Prophets and lesser deities act as intermediaries between the living and the dead, communicating with the elders in society. Believers honour the deities through sacrifices, and pray for good health, bountiful harvests and numerous children.

  Did you know?
Good luck charms worn around the neck are called grisgris (pronounced gree-gree). They must be blessed by a medicine man.
Shamans or medicine men tell fortunes, provide advice on avoiding danger and evil spirits, and make protective fetishes. Fetishes are usually carvings in the shape of a person or an animal. A magical substance, concealed in a hole in its head or abdomen, provides the fetish with its power.

 Islam spread to Congo from North Africa in the mid-19th century. A small Muslim community exists today in the eastern part of the country.