Islam is the most common religion in Sudan and Muslims have dominated national government institutions since independence in 1956. According to UNDP Sudan, the Muslim population is 97%, including numerous Arab and non-Arab groups. The remaining 3% ascribe to either Christianity or traditional animist religions. Muslims predominate in all but Nuba Mountains region. The vast majority of Muslims in Sudan adhere to Sunni Islam of Maliki school of jurisprudence, deeply influenced with Sufism. There are also some Shia communities in Khartoum, the capital. The most significant divisions occur along the lines of the Sufi brotherhoods. Two popular brotherhoods, the Ansar and the Khatmia, are associated with the opposition Umma and Democratic Unionist Parties respectively. Only the Darfur region is traditionally lacking the presence of Sufi brotherhoods found in the rest of the country.
Shari'a law has been installed by various military regimes, and its application to non-Muslims in the capital was a contentious issue during the negotiations, but it and the other major issues underlying the north–south conflict have been largely resolved in the agreements. Shari'a is to continue to be the basis of the national legal system as it applies in the north; national legislation applicable to the south is to be based on "popular consensus, the values, and the customs of the people." In states or regions where a majority hold different religious or customary beliefs than those on which the legal system is based, the national laws may be amended to accord better with such beliefs. Throughout the country, the application of Shari'a to non-Muslims is to be limited, and courts may not exercise their discretion to impose the harsher physical forms of Shari'a penalties on non-Muslims. Sudan has had three democratic governments since 1956, all of which abolished Shari'a law.
