The aim of the study was to evaluate the incidence of post-surgical infections and to assess management of antibiotic surgical prophylaxis. The survey was carried out by means of a questionnaire in order to obtain diverse information such as demographics, length of pre- and post-operative hospitalization, type of surgery, intervention duration, possible antibiotic prophylaxis and onset of post-surgical infections also monitored by post-discharge ambulatory controls. Four General Surgery and five Obstetrics and Gynecology Departments in Campania (southern Italy) participated in the study, which was carried out from December 2001-January 2002. Overall, 410 questionnaires were collected, referring to as many patients; antibiotic prophylaxis was performed in 385 (93.9%) patients. Antibiotic prophylaxis was generally managed not according to the general principles suggested by the international guidelines either for timing, for its duration or for the route of administration. Substantial differences were also noted in patient selection and antibiotic choice. Surgical site infections were recorded in 0.9% of patients undergoing clean surgery and in 3.6% of patients undergoing clean-contaminated surgery. Distant infections occurred in 1.5% in clean-contaminated surgery. The results of the present study suggest the need for continuous and accurate monitoring of post-surgical infections and the need to adopt appropriate guidelines to improve the management of surgical prophylaxis.