Surveillance activities in Italy during the last 5 years can be summarized in three broad categories: collection of data in order to describe the epidemiological pattern of hospital acquired infections, achieved through multicenter studies, involving hospitals or focused on specialized units; organizational efforts for the implementation of Infection Control Committees in Hospitals stimulated by official guidelines (the 1985 Health Ministry Act on this issue); evaluation of preventive strategies in Italy. Results of a one-day prevalence survey conducted in 1983, involving 130 public hospitals, are presented. Out of 34,577 patients surveyed, prevalence of hospital acquired infection was 6.8% and of community-acquired infections 12.5%. Preliminary results of PRINOS (Preventive Study on Hospital Infections) show a 4.6% incidence rate of infections in 16 surgical wards surveilled. Design of the study and target objectives are discussed.