This study aimed to evaluate the method of medical professionalism development in 47 fleshy medical student joining the Sunday peer club. The mean score of the individual interview, Emotional Quotient (EQ) score, especially in the part of empathy, motivation, security, responsibility and self evaluation were higher than the change from the pretest baseline. After for 4 years follow up, the 22 medical students (46.8%) have became the activists of Faculty of Medicine Prince of Songkla University. The conclusion of this study was that medical professionalism can be developed in medical students.