depression is one of the most serious and prevalent mood disorders. Aging population is an important economic, social, and health challenge of the 21 century. The present study aimed at estimating the prevalence of depression among the Iranian elderly through meta-analysis method. Studies were searched in ISI, Scopus, Pub Med, Google Scholar, and in Iranian databases including Iran Medex, Magiran, SID, and Med Lib using the following keywords: "depression", "prevalence", and "elderly". Data were analyzed using meta-analysis (random effects model). Heterogeneity among the results of the studies was examined by "I" index. Beck, DASS-21, GHQ-28, and G DS questionnaires were used in this study, and analyses were performed using STATA Ver.11. A total of 26 studies in Iran with a sample size of 5781 individuals had been found during 2001 and 2015. Prevalence of depression among Iranian elderly was estimated to be 43% (95% confidence interval (CI):30% - 55%). The findings showed that the prevalence of depression among Iranians were49% in women, 48% in men, 37% in unmarried, and 45%in the married. In addition, the prevalence of very severe, severe, moderate, and mild depression levels were estimated to be 5%, 19%, 33%, and 38% of the participants, respectively. No significant difference was observed between married and unmarried individuals. Most of Iranian elderly suffered from mild depression. There was high level of depression prevalence among Iranian elderly, and women were more depressed than men. So, policy makers must design and run mental health programs to decrease the prevalence of depression among Iranian elderly.