Background - In addition to national surveys on the prevalence of healthcare-associated infections, the Southwest Healthcare-Associated Infection Control Coordination Center conducts an annual prevalence survey among healthcare facilities in its region to raise awareness among all staff about the reality of this infectious phenomenon. Method - This cross-sectional survey takes place on a specific day across all departments of participating facilities. An investigator who is an employee of the facility but not of the specific department determines for each patient whether or not a nosocomial infection is present and completes a questionnaire that is simplified compared to national surveys. Results - Between 1993 and 2004, facility participation increased from 15% to 48%. The prevalence rates of infected patients and infections decreased from 5.7% to 4.2% and from 6.3% to 4.6%, respectively, and have remained stable since 2000. The rate of infected patients in intensive care decreased from 20% to 16%. Urinary tract infections account for an average of 30.5% of nosocomial infections. The rate of patients with urinary tract infections who have urinary catheters has remained stable since 2000 (9.4% in 2004). Conclusion - Conducting regular prevalence surveys is a simple way for each facility to transparently assess trends in nosocomial infections.