Surgical site infections (SSIs) are recognized as a common surgical complication, occurring in about 2-5% of all surgical procedures. SSIs represent the third most frequent nosocomial infection, accounting for 14-16% of all infections observed in hospitalized patients and up to 38% of those observed among surgical patients. Knowledge of incidence, epidemiology, classification, process of wound healing, and pathogenesis of surgical site infection is of great importance. Given the high economic burden that infections provoke, beyond the increased morbidity and mortality, it appears mandatory to improve our tools in order to reduce their incidence, as a reduction of only 0.1% can result in a considerable saving of economic resources to be allocated to other activities, such as screening and prevention programs.