In 2001, the National Prevalence Survey provided a nationwide overview of the use of antibiotics for curative or prophylactic purposes among all hospitalized patients on a "given day"; 90% of public hospitals and half of private hospitals participated in the survey. The prevalence of antibiotic treatment on the day of the survey was 15.9% for all hospitalized patients, 24.3% for short-stay patients, and 46.4% for intensive care patients. On the day of the survey, 4% of hospitalized patients were receiving systemic antibiotics to treat a nosocomial infection and the same percentage for prophylaxis. Among patients receiving antibiotics in short-stay care, 53% were being treated for a community-acquired infection, 18% for a nosocomial infection, and 29% were on prophylaxis. The most common indications were: in intensive care, community-acquired infection (41%) and nosocomial infection (38%); in medical wards, community-acquired infection (71%); and in surgical wards, prophylaxis (52%). Amikacin and glycopeptides were most frequently used to treat nosocomial infections. Fluoroquinolones were the most commonly prescribed antibiotics for nosocomial infections and, across all indications, ranked second, after the amoxicillin/clavulanic acid combination. This is the first nationwide description of therapeutic practices regarding antibiotic therapy in hospitals, based on the characteristics of healthcare facilities, departments, indications, and patient characteristics. (R.A.)