Objective: The Maternal Mortality Ratio is an important health indicator. We presented the distribution and causes of maternal mortality in Islamic Republic of Iran. Materials and methods: After provision of an electronic Registry system for date entry, a descriptive-retrospective data collection had been performed for all maternal Deaths in March 2009- March 2012. All maternal deaths and their demographic characteristic were identified by using medical registries, death certificates, and relevant codes according to International Classification of Diseases (ICD-9) during pregnancy, labor, and 42 days after parturition. Results: During 3 years, there were 5094317 deliveries and 941 maternal deaths (MMR of 18.5 per 1000000 live births). We had access to pertained data of 896 cases (95.2%) for review in our study. Of 896 reported deaths, 549 were classified as direct, 302 as indirect and 45 as unknown. Hemorrhage was the most common cause of maternal mortality, followed by Preeclampsia, Eclampsia and sepsis. Among all indirect causes, cardio -vascular diseases were responsible for 10% of maternal deaths, followed by thromboembolism, HTN and renal diseases. Conclusion: Although maternal mortality ratio in IRI could be comparable with the developed countries but its pattern is following developing countries and with this study we had provided reliable data for other prospective studies.