The thesis’s objectives are to study the history, background of the Dhammaduts under Thai Sangha, forms and dissemination methods and the results of Buddhist dissemination of the Dhammaduts at Kasetwisai District, in Roi-Et province according to the Buddhists’ opinions at Kasetwisai district, in Roi-Et province. The research methods are provided as qualitative process and collecting data in the field by observation and interview

            The result of research was found that on the Buddhist dissemination in the Buddha’s period, Lord Buddha had been the sermon preacher by himself as being the king of Dhamma, with many forms and dissemination methods and having the excellen dissemination  quality. He had focus on the permanent benefit of listeners. Later, He gave the opportunity of  Buddhist  to dissemination the followers even if in the Buddha’s time. The Dhammaduts still follow the Buddha’s good method of dissemination by using the instructive media and activities in harmony with the conditions of economics, society and politics. They also were supported by the kingdom in the forms of law and four necessary factors and then Buddhism would be progressive until the present times. For the Dhammaduts affairs in Thailand, the Religious Affairs Department had restored and managed them until getting the impact as satisfiable and then gave the authority to the sangha supreme Council for accepting these affairs as the Sangha’s Buddhist dissemination affairs in 2507 B.E and in two years later, the the sangha supreme Council had the resolution of getting these affairs in the forms of Dhammaduts! by setting it as the permanent activity.

            The Dhammaduts’ dissemination on Buddhism at Kasetwisai Roi-Et province had followed the the sangha supreme Council’s rules and commands by having many forms and dissemination methods. Each of them had different style acccording to the tradition, the belief, conditions of society, economics and politics.  For the principles of Dhamma for dissemination, there were no the permanent forms and the Dhammaduts themselves could apply Dhamma for their own propagation, with their own methods as individual ability and by their own diligence to develop the propagation capacity.

            On the overall images of samples used in this research, the Dhammaduts had used many groups of Dhamma including the ideas and epigams in the present times by considering about suitability for sex, age, career, and condition of economics, society and politics. They also used the Dhamma and mixed them with the creative activities. The instructive media for dissemination as different were under each Dhammaduts knowledge, expert and environments around the listeners. For the benefit and worth in overall views, it was found that the listeners had received the benefit in these ways; physical, mental, economics, and society at the better level.