To investigate the epidemiology trend and characteristics of sepsis-related hospitalizations in Taiwan, and to compare the differences among different severity levels of sepsis.This study is a retrospective national claim database analysis. Hospitalized adult patients with sepsis between 2010 and 2014 were identified from the Two-Million-Sample Longitudinal Health and Welfare Database (LHWD) by the International Classification of Diseases 9th Edition Clinical Modification (ICD-9-CM). The patients were divided into 3 severity groups based on their medical records during hospitalization.The study results showed that in Taiwan, there were 643 new cases of sepsis in 100,000 Taiwanese. The mortality of all septic patients in Taiwan was 287 per 100,000 people, and the case fatality was 29.2%. It was found that the mortality and incidence of sepsis in Taiwan have increased year by year, but there has been no significant change over time. In addition, demographic variation exists in the epidemiology of sepsis. In all the rates investigated, the men's were higher than the women's and the elderly's were higher than the youths'. The analysis results also showed that the respiratory system was the most common site of organ failure in septic patients.The incidence and mortality of any severity level of sepsis were 643, and 287 per 100,000 people in Taiwan, respectively, and the average case fatality was 29.2% during the study period (2010-2014). The respiratory system was the major infected site and site of organ dysfunction, especially in the more severe levels.