This is a qualitative investigation aimed at analyzing the Bai Sri Su Khwan Ceremony of Phu Tai and Tai Lao people in North-eastern Thailand. Tools used for data collection were survey, participant and non-participant observation, structured and unstructured interview, focus group discussion and workshop. Data was collected by field study and document research. The study began in October 2012 and was concluded in October 2013. Results show that the Bai Sri Su Khwan or Thai blessing ceremonies of Phu Tai ethnic groups in Isan are performed for both auspicious and inauspicious reasons. The Phan Bai Sri is a symbolic tree-like ornament used for the ceremony and a Mor Soot will lead the rites. There are seven components to the Bai Sri Su Khwan Ceremony of the Phu Tai and Tai Lao people in Isan.