The Roman Catholic Church - the largest branch of Christianity - says there are a total of 1.086 billion baptised members around the globe.
This figure is expected to exceed 1.1 billion in 2005, with rapid growth in Africa and Asia. However, there are no reliable figures for the number of practising Catholics worldwide. Click on the links below for facts about selected countries.
The Americas have the lion's share of baptised Catholics, with 49.8% (approx 541 million); Europe accounts for 25.8% (approx 282 million); Africa has 13.2% of the total (approx 143 million); Asia - 10.4% (approx 113 million); Oceania - 0.8% (approx 9 million).
Total population: 176.9m
Number of Catholics: 151.2m (85%)
History: Brazil is the country with the largest baptised Roman Catholic population in the world. The faith took root after Jesuit missionaries arrived in the wake of the early Portuguese explorers of the 16th Century. It became the dominant religion in Brazil as well as most other countries in the region. However, official Brazilian statistics suggest evangelical Protestant churches have been making inroads in recent years.
Total population: 1.31bn
Number of Catholics: About 13m (1%)
History: Although Catholicism first reached China in the 7th Century, concerted missionary efforts did not start until the 16th Century. By 1949, the Church was estimated to have 3m baptised members. But China's new Communist rulers, suspicious of foreign links, expelled foreign clergy and missionaries and official ties with the Vatican were broken off. A state-sanctioned Church for Catholics (set up in 1957) is now estimated to have more than 5m members. But an "underground" Church with allegiance to Rome also exists and is reported to have about 8m members.
Total population: 11.3m
Number of Catholics: 6.3m (56%)
History: Roman Catholicism arrived with Spanish colonisers in the 16th Century, and became the dominant faith. After Fidel Castro swept to power in 1959, Cuba became an officially atheist country and curbed religious freedom. The Church was not banned outright, but Catholics were targeted in other ways. A recent spell of rapprochement with Rome saw Christmas reinstated as a national holiday and a visit to Cuba by Pope John Paul II in 1998.
Total population: 52.8m
Number of Catholics: 29.5m (56%)
History: Roman Catholic missionaries first arrived in the coastal region in the late 15th Century in the wake of Portuguese explorers. But despite initial successes, the Church did not put down lasting roots until centuries later. The faith prospered under Belgian colonial rule in the early 20th Century, and has played a significant role by running primary and secondary schools as well as hospitals and other institutions.
Total population: 824,000
Number of Catholics: 767,000 (93%)
History: East Timor - which became independent in 2002 after more than four centuries of foreign rule - is one of only two majority Catholic states in East Asia (the other is the Philippines). Portuguese traders went to Timor in the 16th Century, followed soon after by missionaries. East Timor was annexed by Indonesia after the Portuguese left in 1975.
Total population: 1.07bn
Number of Catholics: 17.3m (1.6%)
History: Christianity and the establishment of churches in southern India is reputed to date from the arrival in the 1st Century of Thomas, a disciple of Jesus. The 16th Century saw the arrival of Roman Catholic missionaries in the wake of Portuguese explorer Vasco da Gama. Roman Catholicism has grown to become the biggest Christian church in India, found mostly in the south and east.
Total population: 57.6m
Number of Catholics: 55.8m (96%)
History: Christianity arrived in the 1st Century and Italy has remained true to the Church of Rome while schisms over the centuries saw first Orthodox Christians and then Protestants breaking away. Polish-born John Paul II became the first non-Italian pope for 400 years when he was appointed in 1978. Although the baptism rate is traditionally high, Catholic congregations have been falling, birth rates shrinking and numbers taking religious orders have also decreased.
Total population: 104.7m
Number of Catholics: 93.6m (89%)
History: Spanish adventurers accompanied by Roman Catholic clergy reached Mexico in the early 16th Century, leading to conquest and rule by Spain of what became known then as New Spain. Mexico won independence in 1821, but Catholicism has remained the dominant religion. However, evangelical churches have reported steady and significant growth for more than three decades.
Total population: 126.1m
Number of Catholics: 18.9m (15%)
History: Catholicism arrived in Nigeria with the Portuguese in the 15th Century. However, it had all but disappeared 200 years later despite the building of churches. Renewed mission work began in earnest in 1865 when priests arrived in Lagos. The Catholics were particularly active among the Igbo community in the south and set up schools and health facilities.
Total population: 81.1m
Number of Catholics: 66.4m (81%)
History: After explorers landed in the 16th Century, Spanish forces moved in and colonised the Philippines for more than three centuries. Missionaries also converted large numbers who believed in native gods and Islam. Although Spanish rule ended after a revolt in 1896, the country remains overwhelmingly Catholic.
Total population: 38.6m
Number of Catholics: 36.9m (95%)
History: Christianity began to take hold in the 10th Century after a leading nobleman was baptised. Poland became staunchly Catholic and the faith has played a significant role in Polish history - particularly in the collapse of Communism in the 1980s. But despite the immense popularity of Polish-born Pope John Paul II, the Church now faces new challenges: attendance is falling in urban areas even though an overwhelming majority still describe themselves as Catholics.
Total population: 41.1m
Number of Catholics: 38.5m (94%)
History: Christianity came early to Spain and the faith was firmly established when Muslim forces from North Africa invaded in the 7th Century and set up a state. They ruled all but northerly areas until a Christian "reconquest" campaign was completed in 1492. Until recently among the most devout European countries, Spain has seen the power and authority of the Church wane. Opinion polls suggest that nearly half of Spaniards now rarely go to Mass.
Total population: 26.7m
Number of Catholics: 11.2m (43%)
History: Catholic missionaries arrived in the southern kingdom of Buganda in 1879, in the wake of Protestant counterparts, after visits by European explorers. The missions set up schools in the quest for hearts and minds as well as commercial spheres of influence. Some recent estimates suggest that the Christian community is evenly split. The Muslim faith and indigenous beliefs account for most of the rest of the population.
Total population: 292m
Number of Catholics: 66.3m (22%)
History: Roman Catholicism arrived with Spanish explorers and settlers in the 16th Century. But numbers remained relatively small until waves of mass emigration in the 19th Century brought millions from countries such as Ireland, France, Germany and Italy. Later arrivals from Latin America have also swelled numbers. Recent years have seen the Church embroiled in a scandal over the sexual abuse of minors by clergy and the handling of the crisis by its leaders.