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 14.6% of all infections observed in hospitalised patients and 38% of those observed among surgical patients. Strategies for the prevention of SSIs also include surveillance which has proved very effective. The most recent surveillance study carried out at a national level in Italy is Kir-Nos, a multicentric study sponsored by GlaxoSmithKline and performed between April and June 2002 in 32 different General Surgery Units for a total of 2972 surgical patients enrolled. Results emerging from the study clearly indicate that many patients receive inappropriate antimicrobial prophylaxis, especially in terms of drug choice, route and timing of administration. 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.