The country has an area of 1,068,302 square miles and a population of 37 million, according to the 2001 census. A 2008 estimate of the population is 40.7 million. Accurate estimates of religious affiliation are difficult to obtain due to legal prohibitions on including religion in the census; however, data from a study conducted by the National Council of Scientific and Technical Research (CONICET) and the National Agency for the Promotion of Science and Technology (FONCyT) produced the following estimates: Roman Catholics, 76 percent of the population; agnostics or atheists, 11 percent; and Pentecostals, 8 percent. Baptists, Jews, Jehovah's Witnesses, Lutherans, Methodists, members of The Church of Jesus Christ of Latter-day Saints (Mormons), Muslims, Seventh-day Adventists, and adherents of the Universal Church of the Kingdom of God total fewer than 5 percent of the population.
The Islamic Center estimates that one of every three Middle Eastern immigrants is Muslim. Descendants of Syrian and Lebanese immigrants, approximately half of whom are Orthodox Catholic or Maronite, constitute a significant portion of the population with Middle Eastern roots. The Muslim community is composed of 500,000 to 600,000 members, of whom 70 percent are Sunni and 30 percent Shi'ite, according to estimates by the Sunni-dominated Islamic Center.
Leaders of diverse religious groups noted the recent growth of evangelical Protestant communities due to conversion, principally in newer evangelical churches. Religious leaders also noted the impact of global secularization on religious demography.