The report covers the history, community, socio-economy, culture, livelihood, life cycle, traditions, and rituals of the Lao Song at Don Sai Village, Tambon Thap Khang, Kao Yoi District, Phetchaburi Province. The ethnic group originated in Sipsongchuthai State (northern Vietnam) and was brought to Siam during the Thonburi and early Ratanakosin Periods. The village is a peasant community growing rice as well as vegetables and raising livestock. The family is of the nuclear type and the social system is matrilineal. Rituals play an important role in the life of a Lao Song. The ethnic group believes that everything is under the power of supernatural beings, therefore sacrificial rituals must be conducted on a regular basis for the well being of community members.