Surgical site infection (SSI) is one of the most frequently reported types of healthcare-associated infections. For the period 2018–2020, the European Centre for Disease Prevention and Control reports that 42% of SSIs were classified as superficial, 30% as deep and 28% as organ/space. The proportion of deep or organ/space SSIs ranged from 27% for cesarean section to 81% for hip prosthesis surgery. Based on data from the USA, SSIs are linked to a significant increase in the risk of mortality, ranging from 2 to 11 times higher. The prevalence of SSIs exhibited significant variation depending on the type of surgical procedure. The financial burden of SSI is due to the patient’s extended hospitalization, delayed recovery, supplementary diagnostic tests, treatment, reoperation, readmission, transient or permanent loss of function in the affected region and death. In the USA it was estimated that SSI prolongs hospital stays by an average of 9.7 days, leading to an additional cost of over 20,000 USD per admission. In conclusion, estimating the frequency, the burden and the additional cost burden caused by the SSI helps to understand how important it is to reduce healthcare-associated infections and prioritize interventions.