Nurses' Involvement in activities of all 10 steps of the process concerning Thailand International Public Sector Management System and Outcomes (P.S.O.) is very importantfor the success of being accredited of the hospital. This study aimed to determine types of involvement in Hospital Accreditation activities among profession nurses of CommunityHospitals Sukhothai Province. The sample were 139 registered nurses who had more thanone year work experiences and were not leave for their education. The data were collectedusing a questionnaire developed by the investigator consisted of 3 part: personal data, typesof involvement in 10 step of the P.S.O. process according to Reilly (1979), and problems and barriers of involvement. The content validity was assured by means of three expectswith the content validity index of 0.81. Reliability tested by test-retest method using Spearman Rank Correlation Coefficient was 0.92. The data were analyzed by using descriptive statistics. The results of this study were: 1. The most common type of the subject' involvement in activities of ten steps of the P.S.O. process was type 5: employees jointly make decision with management. When examiningthe individual step, it was found that the subjects demonstrated type 5 of involvement in step1, 2, 3, 4, 5, 6, 7, 8, and 10. In step 9 the most common type of involvement was type 2 : employees informed of decision once taken. 2. When separately examining the type of involvement among the nurses with administrativeposition and the staff nurses, there were not significantly different ( p > 0.05). Subjects isboth groups demonstrated type 5 of involvement : employees jointly make decision withmanagement. When examining the individual step of process, it was found that the subjectsdemonstrate type 5 of involvement in step 1, 2, 3, 4, 5, 6, 7, 8, and 10. However, of the nurseswith administrative position demonstrated type 2 and type 5 of involvement in step 9 and the staff nurses demonstrated type 5 of involvement. 3. The problems and barriers of nurses' involvement in activities concerning Hospital Accreditation process were not many. The top three problems and barriers were the nursingpersonnel had insufficient knowledge regarding the process of P.S.O. high workload withintheir unit, and different working time. The results of this study could be used for encouraging nurses involvement in the P.S.O.process which will lead to the accreditation of Community Hospitals Sukhothai Provincein the future.