CLINICAL EPIDEMIOLOGICAL CHARACTERISTICS AND DYNAMICS OF LABORATORY INDICATORS IN PATIENTS WITH HEMORRHAGIC FEVER WITH RENAL SYNDROME OBJECTIVES: The aim of this study is to determine the clinical and epidemiological characteristics of HFRS, to examine whether there is a connection between clinical entity (expressed by clinical and laboratory indicators) and individual serotypes of the causative agent, and to determine the share of HFRS patients in the total number of hospitalized infectious patients in the observed period. STUDY DESIGN: A prospective study with historical data. PARTICIPANTS AND METHODS: Taking into account the inclusion criteria (clinically and laboratory-proven symptomatic HFRS) the study included all patients with HFRS treated at the Clinic for Infectology of the Clinical Hospital Center Osijek in the period from January 2017 to December 2023. Demographic, epidemiological, clinical and laboratory data were collected and analyzed from the history of illness. RESULTS: HFRS was found in 34 patients, mostly middle-aged men. The majority of patients live in rural areas, and are infected by staying in nature. 24% of patients have DOBV, and 76% have PUUV infection. All patients had a general infective syndrome, while 53% had pain in the lumbosacral region. Thrombocytopenia is present in all patients. Serum creatinine, CRP, D-dimers and fibrinogen were elevated in all patients. Most of the patients had proteinuria and erythrocyturia, and a few had pathological findings on abdominal ultrasound and lung X-rays. There is no significant difference in relation to the type of virus. The patients were treated symptomatically, most of them with antimicrobials as well. All patients recovered. CONCLUSION: The research showed that the demographic and epidemiological data, the clinical picture, and the findings of laboratory and imaging tests correspond to a typical HVBS infection, although without undoubted differences with regard to the type of virus.