Islam is most popular in southern Thailand, near the border with Malaysia, where the vast majority of the country's Muslims, predominantly Malay in origin, are found. The remaining Muslims are Pakistani and Bangladeshi immigrants in the urban centers, ethnic Thai in the rural areas of the Center and South (varying from entire Muslim communities to mixed settlements), and a few Chinese Muslims in the far north. Also, Cambodian Muslims can be found between the mutual border and Bangkok as well as the deep south. Education and maintenance of their own cultural traditions are vital interests of these groups.

Except in the small circle of theologically trained believers, the Islamic faith in Thailand, like Buddhism, had become integrated with many beliefs and practices not integral to Islam. It would be difficult to draw a line between animistic practices indigenous to Malay culture that were used to drive off evil spirits and local Islamic ceremonies because each contained aspects of the other. In the mid-1980s, the country had more than 2,000 mosques in 38 Thai provinces, with the largest number (434) in Narathiwat province. All but a very small number of the mosques were associated with the Shi'a branch of Islam; the remainder were of the Sunni branch. Each mosque had an imam (prayer leader), a muezzin (who issued the call to prayer), and perhaps other functionaries.

Although the majority of the country's Muslims were ethnically Malay, the Muslim community also included the Thai Muslims, who were either hereditary Muslims, Muslims by intermarriage, or recent converts. Cham Muslims originally from Cambodia; West Asians, including both Sunni and Shias; South Asians, including Tamils, Punjabis and Bengalis; Indonesians, especially Javanese and Minangkabau; Thai-Malay or people of Malay ethnicity who have accepted many aspects of Thai language and culture, except Buddhism, and have intermarried with Thai; and Chinese Muslims, who were mostly Hui living in the North.

It is interesting to note that Thai Muslims of the Chinese Hui extraction are called Chin Ho in the Thai Language. Whereas the name Chin Ho can be explained to be a combination of "Chin" (China) and "Ho" (Hui), it also bears a striking similarity in pronunciation to the name of Zheng He, one of the first great Imperial Chinese diplomats to have visited Thailand in its early Siamese history, who was also of the Chinese Hui extraction. The Chin Ho people, thus, can be seen as "The People of Zheng He"---traders and emigres who carried with them Hui Muslim traditions from China.

The National Council for Muslims, consisting of at least five persons (all Muslims) and appointed by royal proclamation, advised the ministries of education and interior on Islamic matters. Its presiding officer, the state counselor for Muslim affairs, was appointed by the king and held the office of division chief in the Department of Religious Affairs in the Ministry of Education. Provincial councils for Muslim affairs existed in the provinces that had substantial Muslim minorities, and there were other links between the government and the Muslim community, including government financial assistance to Islamic education institutions, assistance with construction of some of the larger mosques, and the funding of pilgrimages by Thai Muslims to Mecca, both Bangkok and Hat Yai being primary gateway cities. Thailand also maintained several hundred Islamic schools at the primary and secondary levels, as well as Islamic banks, (Pattanakarn, Bangkok), shops and other institutions. Much of the packaged food marketed is tested and labelled halal (unless it has pork), regardless of who eats it.

Source : http://en.wikipedia.org/wiki/Islam_in_Thailand