The country has an area of 91,699 square miles and a population of 21.7 million. According to the 2002 census, Romanian Orthodox believers (including the Orthodox Serb Bishopric of Timisoara) comprised 86.8 percent of the population. Roman Catholics 4.7 percent, and Greek Catholics less than 1 percent. The Greek Catholic Church claimed that their church membership was undercounted in the official census and estimated that its adherents comprise 3.6 percent of the population. The following religious groups comprised less than 2 percent of the population: Old Rite Russian Christian (Orthodox) Church, Protestant Reformed Church, Christian Evangelical Church, Romanian Evangelical Church, Evangelical Augustinian Church, Lutheran Evangelical Church, Unitarian Church of Romania, Baptist Church, Apostolic Church of God (Pentecostal Church), Seventh-day Adventist Church, Armenian Church, Judaism, Islam, Jehovah's Witnesses, the Baha'i Faith, the Family (God's Children), the Church of Jesus Christ of Latter-day Saints (Mormons), the Unification Church, the Methodist Church, the Presbyterian Church, Transcendental Meditation, Hare Krishna, and Zen Buddhism.
Most religious groups have followers dispersed throughout the country, although a few religious communities are concentrated in particular regions. Old Rite members (Lippovans) are located in Moldavia and Dobrogea. Most Muslims are located in the southeastern part of the country. Most Greek Catholics reside in Transylvania, but there are also Greek Catholics in Bucharest and the Banat and Crisana regions. Protestant and Catholic believers tend to be in Transylvania, but many also are located around Bacau. Orthodox and Greek Catholic ethnic Ukrainians live mostly in the northwestern part of the country. Orthodox ethnic Serbs are primarily in Banat. Armenians are concentrated in Moldavia and the south. Members of the Protestant Reformed, RomanCatholic, Unitarian, and Lutheran churches from Transylvania are virtually all ethnic Hungarians.
Approximately 31 percent of the population claims to attend religious services several times a month, according to a September 2007 poll.