The main purpose of this survey research was to study the knowledge and opinions of medical personnel and insured persons toward medical service provision according to the Social Security Act B.E.2533 (SSA). A comparision on knowledge, opinions, influencing factors, problems, obstacles

and possible measures was also made between medical personnel and insured persons. A total of 510 samples, including 218 medical personnel (140 from public and 78 from private hospitals) and 292 insured persons (183 from industrial factory and 109 from company) who had use services from October 1992 to January 1993 were chosen for the study. It was found that medical personnel in public hospitals had medium level of knowledge and high level of opinion while medical personnel in private hospitals had high level of both knowledge and opinion toward medical services. The knowledge of both groups was significantly differences (P = 0.008) in which medical personnel in private hospitals had more knowledge than those in public hospitals. But no significantly differences was found between their opinions (P > 0.05). Insured persons in industrial factory and company also had medium level of knowledge and opinions toward medical services without significant differences (P > 0.05). There was no correlation found between their knowledge and opinions. However, the knowledge and opinions of medical personnel and insured persons were significantly differences (P < 0.0001) in which the knowledge and opinions of medical personnel were better than insured persons. The main problems of medical services under the SSA were inflexibility of hospital selection, complicated procedures, lack of confidence in medicine according to national drug list, inappropriate requirements, lack of knowledge and insufficient information from SSA office. It is,therefore suggested from the study, that same effective measures be introduced to continuously disseminate information to involved medical personnel and insured persons by using different means of communication. Some administrative aspects of the SSA must also be modified to fit the present socio-economic situation of the country.