Introduction: Unhealthy lifestyle causes complications and requires more attention to education and health promotion programs among various social groups. Therefore, this study was conducted to determine the effectiveness of peer education on health- promoting lifestyle in health volunteers. 

Methods: In this quasi-experimental study, firstly through convenience sampling method,59 cases from four centers subset health center of Mashhad were selected based on the results of the pilot study. Then through random assignment, two centers were devoted to experimental group (29 person) and two other centers to control group (30 person). In the experimental group, after selection peer educators, educational intervention was performed in 6 sessions. 45-60 minutes in the form of small groups and cooperative learning. Common application of centers was performed in the control group. In both groups, lifestyle norm questionnaire was filled out before and four weeks after the intervention. Data Analysis was done using SPSS V.16 as well as t-test, Mann-Whitney U, Wilcoxon, and Chi-Square Test.

Results: After intervention, mean scores of health promoting lifestyle showed a significant increase in the experimental group in all aspects compared with before intervention (P<0.001). While the control group observed no significant increase in all aspects except health responsibility (P>0.05). Difference of mean Scores in all aspects of lifestyle in the experimental group were statistically significant compared with the control group (P<0.001). 

Conclusion: Peer education is effective in improving the lifestyle of health volunteers. Therefore, the use of peer education is recommended in health volunteers training.