Introduction:Hospital-acquired infections (HAI) and surgical site infections (SSI) are a global public health problem. The aim of the study was to determine the incidence of SSIs at the Surgical Clinics of the University Clinical Centre Banja Luka and to identify risk factors for the development of SSIs.Methods:In order to determine the frequency of SSIs through the incidence compared to the patients operated at the Surgical Clinics of the University Clinical Centre Banja Luka, we conducted a prospective cohort study which encompassed 11.216 operated patients, in the period from November 11th, 2014 to September 30th, 2015. In order to identify risk factors for the development of SSIs, a nested case-control study of risk factors for SSIs was conducted. The study group consisted of patients who were diagnosed with SSIs in the period of monitoring, while the control group was consisted of patients without SSIs who corresponded with the study group in age and sex.Results:The highest values of incidence of SSIs were observed at the Department of Anesthesia and Intensive Care (2.65%), Department of Orthopaedic Surgery (2.48%) and the Department of Vascular Surgery (2.15%), and the lowest ones at the Department of Urology (0.59%). Among the cases of SSIs, deep infections of the surgical site were the most represented (82.7%). Multivariate logistic regression was used to identify the following independent risk factors: length of pore-operative stay in hospital (p=0.000; OR=1.062; 95% CI=1.037-1.087), reintervention (p=0.000; OR=22.409; 95% CI=6.361-79.071) and cotrticosteroids (p=0.023; OR=4.141; 95%CI=1.221-14.047).Conclusion:The incidence of SSIs at the Surgical Clinics of the University Clinical Centre Banja Luka is at the level of hospitals in developed countries. There are a number of risk factors for SSIs, which may be prevented.