The majority of the Vietnamese migrating into Thailand were prisoners of war and refugees from political and religious persecution. The latter came through Laos and settled along the Mekong River in Tha Uthen, Chaiburi, Nong Khai and Nakhon Phanom. They were both Buddhists and Christians. The Vietnamese in the Isan region are divided into old and new Viet Kieu. When they first arrived, they lived in huts made from cement-coated bamboo and suppressed ground floor. Some built row houses with foldable front doors. They dressed like the Chinese, spoke Vietnamese and ate bland food with vegetables as condiments. They were Buddhists, Christians and animists believing in supernatural power, deities, and spiritual mediums. They had their own marriage ceremony and funeral rituals. Presently, they live in modern concrete houses and speak Vietnamese, Standard Thai, the Isan Thai dialect and other foreign languages. They wear modern clothes on a daily basis and traditional costumes during festivals. They eat Vietnamese, Thai, Isan, Chinese and Western foods. They are Buddhists, Christians and animists. They observe their traditional New Year holiday and funerals. Some of the problems found include traditional houses being disappearing, younger generations refusing to speak Vietnamese and most migrant people reverting to wearing modern clothes. The traditional costumes are only worn at festivals and are now modernized. They do not like to eat Vietnamese food. Religious activities are conducted separately according to their faiths. Spiritual mediums have been disappearing and no one wants to carry on the practice. Acculturation has brought about socio-cultural changes. For their identity and assimilation, it is found that they live in Thai-style houses, speak Standard Thai and Isan Thai dialect, and take part in religious and cultural activities with the locals, so that they are becoming culturally assimilated. Therefore, their identity and assimilation are influenced by the mainstream Thai culture.