Background Iran was one of the first countries to be affected by COVID-19. Identifying factors associated with the severity of COVID-19 is useful in disease management. This study investigated the epidemiological and clinical features and factors related to severe COVID-19 in Iran's less-privileged area.MethodsIn a multicenter study, all patients admitted to Zahedan University of Medical Sciences hospitals located in southeastern Iran were investigated from February 29 to April 31, 2020. The demographic, epidemiological, and clinical data of patients were extracted from medical records. To explore the risk factors associated with the severity of COVID-19, bivariate and multivariate logistic regression models were used. ResultsAmong the 413 patients, 55.5% were male, and 145 (35.10%) were in severe condition at admission time. Multivariate analysis showed that the adjusted odds of the disease severity increased in patients with older age (OR 3.51; 95% CI, 2.28-5.40), substance abuse (OR 2.22; 95% CI, 2.05-5.78), and at least one underlying disease (OR 3.45; 95% CI, 1.01-1.32).Conclusions COVID-19 was more severe in older patients, patients with a history of substance abuse, and patients with at least one underlying disease. Understanding the factors affecting the disease severity can help for the clinical management of COVID-19, especially in less privileged areas where fewer resources are available.