As part of a national program for the control of hospital acquired infections, a survey on the use of antibiotic chemoprophylaxis was conducted in 1050 public hospitals in Italy (95% of the total number of hospitals in the country). In each hospital, the chief of the general surgery ward was interviewed by means of a standard mail questionnaire. Answers were obtained from 479 surgeons (45.6%) after two mailings. More than 60% of these reported that they used chemoprophylaxis in clean surgery (mastectomy, splenectomy, hernioplasty). More than 80% used antibiotic prophylaxis in surgery in which antimicrobial prophylaxis is facultative (i.e. elective cholecystectomy, gastric resection), and 97.1% used antibiotic prophylaxis in large bowel surgery. The authors recorded starting times and duration of chemoprophylaxis. Cephalosporins were found to be the most commonly used antibiotics followed by penicillin.