Estonia's constitution guarantees freedom of religion, separation of church and state, and individual rights to privacy of belief and religion. According to the Dentsu Communication Institute Inc, Estonia is one of the least religious countries in the world, with 75.7% of the population claiming to be irreligious. The Eurobarometer Poll 2005 found that only 16% of Estonians profess a belief in a god, the lowest belief of all countries studied (EU study).
The largest religious faith in the country is Evangelical Lutheranism, adhered to by 152,000 Estonians (or 14.8%) of the population, principally ethnic Estonians. 143,000 inhabitants follow the Eastern Orthodox Christianity, practised chiefly by the Russian minority.
According to the census of 2000, there were about 152,000 Lutherans, 143,000 Orthodox Christians, 5,000 Roman Catholics, 4,268 Jehovah's Witnesses, and 1,000 adherents of Taaraism or Maausk in Estonia (see Maavalla Koda). The Jewish community has an estimated population of about 1,900 (see History of the Jews in Estonia). In addition, around 68,000 people consider themselves atheists.
The country was Christianised by the Teutonic Knights in the 13th century. During the Reformation, Protestantism spread, and the Lutheran church was officially established in Estonia in 1686. Still, many Estonians profess not to be particularly religious, because religion through the 19th century was associated with German feudal rule. Historically, there has been another minority religion, Russian Old-believers, near Lake Peipus area in Tartu County