Background and Aim: Due to the increase number of articles publishing in scientific journals, as well as the importance of their quality in the production and transmission of knowledge in medical sciences, the current study aimed at assessing the quality of the published papers in the Journal of Birjand University of Medical Sciences before and after of their peer review. Materials and Methods: In this descriptive analytical study, the quality of original research articles published in the Journal of Birjand University of Medical Sciences during 2012 was evaluated before and after their peer review. Means of collecting the necessary data was a checklist with 84 items regarding each article, which was completed before and after peer reviewing process. A 5-point scale was used for every item. One sample t-test and paired t-test were used to compare the scores and P<0.05 was taken as the statistical significant level. Results: Totally, 46 original research articles were evaluated whose mean total score in the first edition was 3.36±0.54 and in the respective printed version it was 4.32±0.28, which was moderate to high. . Comparison of the mean scores before and after peer reviewing showed some improvement in the quality of all parts of the articles (P<0.001). Conclusion: Peer review improved the quality of articles, particularly in the titles, editing and findings. Since accurate medical research reports in the correct information transfer to professionals and researchers, what JBUMS has done can be useful and valuable.