Abstract Background Necrotizing soft tissue infections (NSTI) are emergency surgical conditions with severe physiologic and metabolic derangement. These infections are associated with increased rates of mortality and morbidity worldwide, particularly in developing countries if not diagnosed and treated early. Methods This prospective, observational cohort study includes all patients aged 12 and above who presented at Department of Surgery, University Teaching Hospital of Kigali from April 2016 to January 2017 with NSTI. We describe epidemiology, operative management, and outcomes of care. We determined risk factors for mortality using multivariate logistic regression. Results We identified 175 patients with confirmed diagnosis of NSTI. The majority of patients (53%) were male, and the mean age was 44 years. The median duration of symptoms was 8 days [interquartile range (IQR) 5–14]. The median length of hospital stay was 23 days (IQR 8–41). The overall mortality was 26%. Multivariate regression analysis revealed four independent predictors of mortality: presence of shock at admission [odds ratio (OR) 14.15, 95% confidence interval (CI) 0.96–208.01, p = 0.050], renal failure (OR 8.92, 95% CI 1.55–51.29, p = 0.014), infection located on the trunk (OR 5.60, 95% CI 0.99–31.62, p = 0.050), and presence of skin gangrene (OR 4.04, 95% CI 1.18–13.76, p = 0.026). Conclusion In Rwanda, NSTI mortality is high and associated with advanced disease. It is imperative that efforts are focused on early consultation, diagnosis, and surgical management to prevent adverse outcomes.