According to a 2001 study, about 84% of the population belongs at least nominally to the Bulgarian (Eastern) Orthodox Church, now considered the traditional religion of the state. There are also an estimated 12% who are Muslims. A 1998 study placed other religious affiliation at 1.5% Roman Catholic, 0.8% Jewish, 0.2% Uniate Catholics, and 0.5% Protestants, Gregorian-Armenians, and others.
After seizing power in 1946, the Communist regime eliminated its opponents from among the clergy. The government, whose aim was eventually to establish an atheistic society, sought during the ensuing period to replace all religious rites and rituals with civil ceremonies. The new constitution of 1991, however, guarantees freedom of religion to all. Diplomatic relations with the Vatican had already been established in 1990. The constitution provides for religious freedom; however, the government restricts this right in practice for some non-Orthodox religious groups. The law requires religious groups to register with the Council of Ministers; this requirement presents an obstacle to activity for some religious groups. Such lack of registration presented an obstacle for Jehovah's Witnesses early in 1998. In some cases local authorities have used lack of registration as a pretext for interference and employment of arbitrary harassment tactics against some groups. In 1998 a small number of religious groups continued to come under attack and were unable to conduct services freely; such reports ceased by 1999.