Background: Maternal near-miss refers to a situation where a woman who nearly died but survived from severe life-threatening obstetric complications that occurred during pregnancy, childbirth or within 42 days of termination of pregnancy. It has been estimated that up to 9 million women survive obstetric complications every year. According to studies done around the world most mothers suffer from Near Miss due to the factors which includes, low socioeconomic status, patient related, health provider related, and health related and health institution related issues. Objectives: The objective of the study was to determine the proportion of maternal near misses and its associated factors in Selected Public Health Institutions of Keffa, Bench-Maji and Sheka Zones of South Nations Nationalities and Peoples Regional state, South West Ethiopia, 2017. Methodology: Hospital based cross-sectional study design was employed and simple random sampling techniques (Lottery Method) was used to select the study institution and Systematic sampling technique was used to select 845 study participants every 5^th interval. Information was collected by using pre-tested and structured interviewer administered questioner. Using SPSS version 21 software, descriptive statistics and bivariate logistic regression analysis was done and variables with p-value <0.2 were transferred to multivariate analysis and during Multivariate logistic regression analysis Variables with P-value < 0.05 were considered as statistically significant and AOR with 95% CI were used to control for possible confounders and to interpret the result. The results were summarized by tables, graphs and charts. Result: There were 5530 Live Births, 227 Sever Acute Maternal Morbidity cases of this 210 were Maternal Near-Misses cases and 17 were maternal deaths, 364 Maternal Near-Misses Events. The overall Maternal Near-Misses Proportion is 24.85%. The maternal Near-Misses outcome ratio was 41 cases/1,000 live births (LB); mortality ratio was 12.35cases/1 maternal death and 74.8/1000LB of mortality index. Parity, residence, distance of living place from hospital, ANC Follow up, duration of labor, and administrative related problems were found to have statistically significant associations. Conclusion: The proportion of Maternal Near-Misses is relatively high when compared to other regional studies and efforts should be done to lower the near-misses.