The official religion of Bahrain is Islam, which the majority of the population practices. However, due to an influx of immigrants and guest workers from non-Muslim countries, such as India, Philippines and Sri Lanka, the overall percentage of Muslims in the country has declined in recent years. According to the 2001 census, 80% of Bahrain's population was Muslim, 10% were Christian, and 10% practiced other religions.
There are no official figures for the proportion of Shia and Sunni among the Muslims of Bahrain. Unofficial sources, such as the Library of Congress Country Studies, BBC, and the New York Times, estimate it to be approximately 45% Sunni and 55% Shia. The last official census (in 1941) which included sectarian identification reported 53% as Shia.
Bahrain has transformed into a cosmopolitan society with mixed communities: two thirds of Bahrain's population consists of Arabs. A Large contingency of people of Iranian descent as well as immigrants and guest workers from, South Asia and Southeast Asia are present. A Financial Times published on 31 May 1983 found that "Bahrain is a polyglot state, both religiously and racially. Leaving aside the temporary immigrants of the past ten years, there are at least eight or nine communities on the island."
The present communities may be classified as:
* Tribals - Sunni Arab bedouin tribes allied to the Al-Khalifa including the Utoob tribes, Dawasir, Al Nuaim, Al Mannai etc
* Baharna - indigenous Shia ethnic group
* Howala - descendants of Sunni Arabs who migrated to Persia and returned later on
* Ajam - ethnic Persian Shia;
* Najdis (also called Hadhar), non-tribal urban Sunni Arabs from Najd in central Arabia. These are families whose ancestors were pearl divers, traders, etc. An example is the Al Gosaibi family.
* Banyan - Indians who traded with Bahrain and settled before the age of oil (formerly known as the Hunood or Banyan, Arabic: البونيان);
* Afro-Arabs - Descendants of black African slaves from East Africa
* Bahraini Jews - a tiny Jewish community; and a miscellaneous grouping.
