Background: Sleep apnea is a common sleep disorder which is associated with cardiovascular diseases, diabetes and stroke. Different studies conducted in Iran have reported different prevalence for sleep apnea. The aim of the present study was to determine the prevalence of sleep apnea in Iran. Materials and Methods: In this study, 42 studies that have been published in Farsi and English languages were selected with no time limit up to the March of 2018. Article search was conducted using "prevalence", "frequency", "sleep apnea" and "obstructive sleep apnea" keywords in Scientific Information Database (SID), MagIran, Google Scholar, Science Direct, PubMed and Scopus databases. Data were analyzed using meta-analysis and random effect model methods. Heterogeneity between the studies was evaluated using I(2) test. Data were analyzed using Stata software version 11.2. Results: The total prevalence of metabolic syndrome was 44 (95 CI: 35 to 53). The highest prevalence of sleep apnea distinguished by the disease belonged to patients with sleep disorders (74, 95 CI: 66-82), diabetes mellitus (61; 95 CI: 46-76) and cardiovascular disease (55; 95 CI: 47-63). Conclusion: Given high prevalence of sleep apnea in Iran, identifying people at risk and providing instructional materials for controlling and treating sleep apnea is necessary
