Abstract Background: Diabetes is one of the most common and most costly chronic diseases Treatment and prevention of diabetes, largely dependent on the patient's sense of self-efficacy for self-management and adherence to self-care behaviors.. This study was conducted to evaluate the effect of peer on knowledge level in type II diabetic patients. Materials and Methods: In this clinical trial study convenient sample of 80 patients who suffer from diabetes was divided randomly into two equal groups, experimental and control. Peers held ten training -supportive sessions for experimental group during three following months. A valid and reliable (Content validity and Retest) questionnaire DMSES was used for data collection, which interview with the researcher was completed by both of the groups before, and three months after the test. Finally, data analyzed through Chi-square, paired T, and independent T tests. Results: Chi-square test results showed no significant difference between experiment and control groups in demographic characteristics (p<0.05).The results of independent T test did not show any significant difference between self efficacy scores of experimental and control group before intervention (p=0.1). While a statistically significant difference was observed after intervention between the scores of two groups (p<0.001). Paired t test showed a statistically significant difference in self efficacy level in experimental group after intervention (p<0.001). Whereas the same test showed no statistically significant difference in control groups (p =0.001). Conclusion: The finding of this study showed that for completing the formal sanitary caregivers Performance of support peers’ support within the community, Can be used as a method of support - educational effective and affordable, in order to improve the level of self efficacy and self-management behaviors of patients. Key words: type II diabetes, peers’ support, self efficacy level