At St. James Catholic Church in Falls Church, John Baptist N. Mubiru, his wife and three children are almost the only African immigrants in the congregation.

A few dozen Ugandans go to a monthly Saturday Mass with hymns in Luganda -- a Ugandan language -- at Basilica of the National Shrine of the Immaculate Conception in Northeast Washington, but they also attend Sunday Mass at churches that are predominantly white. In Silver Spring, some Africans attend both the English-speaking Masses at St. Camillus and the French-language one.

African Catholics, unlike many other immigrants, worship in dispersed churches across the Washington region. Most of them choose churches that are close to their homes or workplaces, or those with schools for their children, rather than seeking out congregations with other Africans.

But today, as many as 1,000 African Catholics are to come together. The Roman Catholic Archdiocese of Washington is sponsoring its second annual African Gathering Day, and lay leaders are also launching an African Catholic Association. A two-hour Mass that is to include prayers and music in various languages will be held at St. John the Baptist Catholic Church in Silver Spring, followed by a celebration with African stews and baked vegetables and games for children. The day will conclude with a dinner gala.

"We are Catholics, but we are also Africans," said Mubiru, a Ugandan immigrant who was elected president of the new association.

Mubiru, a computer consultant who immigrated in 1979, said the group hopes to raise awareness within the diocese about African Catholics as well as bring African immigrants together to help members with such issues as education, medical care and navigating life in a new country.

"Most people don't recognize us because we are so scattered," Mubiru said. "We have to have a common voice."

The Washington region is home to about 100,000 African-born people, about 10 percent of all African immigrants in the United States -- and the second largest African population in this country, after New York. Half of the Africans in the United States are Christian, including large segments of Catholics, Presbyterians and Anglicans. The rest are Muslims or practice indigenous African religions. The archdiocese does not have an exact count of African Catholics in the Washington region.

Catholicism is growing faster in Africa than on any other continent, with 150 million believers and at least 13 percent of the world's Catholics. The world's largest seminary, with more than 1,000 students, is in Nigeria. This year, a Nigerian cardinal was on the short list to replace Pope John Paul II.

Such growth and energy have traveled to the United States, where church leaders said they are seeing an increasing number of African Catholics. Most are younger people here for an education or better job prospects. African immigrants began arriving in large numbers about 15 years ago because of the U.S. government's issuance of "diversity" visas to a wider range of nationalities.

"For a long time, priests were sent to Africa to evangelize. It was a good thing they did; they yielded much fruit," said Sister Mary Francis Amanfo, national coordinator of African and Caribbean ministries for the Washington-based U.S. Conference of Catholic Bishops. "Now many Africans are here, and they are very active in the church."

Although some Africans have gathered for special Masses in French or other languages, most can speak English and meld into existing congregations.

Marjorie Kambaila, 33, said that when she immigrated from Zambia seven years ago, she decided to live in an apartment complex in Takoma Park because it was on a bus line, within walking distance of a grocery store -- and, most important, next door to a Catholic church.

Our Lady of Sorrows Catholic Church had only a handful of African members at the time, but Kambaila said she immediately felt comfortable.

"The church becomes a solace, where you can sit and find peace," said Kambaila, a receptionist and vice president of the African Catholic Association. "You know you will find the cross there. It's familiar in a foreign land."

Still, Kambaila said she misses singing lively African hymns and spending several hours in church, in contrast to the "pray and leave" style of non-African Masses.

African Gathering Day, she said, "is just this one day when we get to reach out to our cultural heritage."

But afterward, she looks forward to going back to worship at a church where Africans are the minority and parishioners include Asians, Latinos and whites. That, she said, is what makes her feel most at home now.