OBJECTIVES: The aim of this study is to determine the clinical-epidemiological characteristics of sepsis syndrome, and to examine whether there is a correlation between clinical entity (expressed by clinical and laboratory indicators) and the origin of sepsis. The aim is also to examine which inflammatory laboratory indicators could be a prognostic sign for early detection of sepsis in order to enable timely recognition and prompt treatment. STUDY DESIGN: Retrospective epidemiological study. PARTICIPANTS AND METHODS: Taking into account the criterion of inclusion (clinically and laboratory-proven sepsis, regardless of the source of sepsis), the study included all hospitalized patients with sepsis syndrome at the Clinical Hospital Center Osijek, at the Clinic for infectiology in the period from June to December 2016. The history of illness was used to collect clinical, demographic, microbiological, biochemical and hematological data about patients. RESULTS: Sepsis syndrome was diagnosed in 168 patients, men and women equally. Major number of patients had significant comorbidity with the presence of many factors which complicate sepsis. Most patients had fever (64,29 %), fewer had other symptoms of sepsis, like respiratory, urinary and gastrointestinal. 25 patients had positive blood culture, and 40 patients had positive urine culture. The most common isolate was E. coli. Average duration of hospitalization was 7,68 days. The outcome of the disease was mostly positive, and only 9,52 % of patients died. The group with a fatal outcome had higher values of CRP, non-segmented leukocytes, urea, creatinine, AST and had hypoalbuminemia. CONCLUSION: The research has shown that sepsis syndrome participates significantly in the total number of hospitalized patients with infectious diseases. Early recognition and timely treatment of sepsis is important, when we take into account the urgency of treatment, numerous possible complications and the high mortality of sepsis syndrome.