The report investigated the lifestyle of the Yo at Tambon Khlong Nam Sai, Arunyaprathet District, Sakaew Province. Both documentary and field data were collected. The Yo is a Tai ethnic group migrating from Vientiane and Tha Uthen to Cambodia. Due to demarcation problems, they migrated to the Thai border. Their culture, traditions, beliefs and lifestyle are similar to those of Thai and Lao, except in their speech accents. The Yo do not have a writing system. The family is of the extended type with close relationships. They practice subsistence agriculture except highland cultivation, eating plain rice, believing in Buddhism but still conducting animistic rituals. Presently, their houses are semi-concrete with tile roofs and modern facilities. Family planning is implemented, reducing family size. There are five schools, a public health center and there are piped and underground water systems instead of the reliance on canal water.