A one-day prevalence survey was conducted in Calabria (Italy) to estimate the prevalence of hospital-acquired infections (HAI) and the effect of different variables on HAI in 888 patients present in a ward for at least 24 hours and not due for discharge or transfer on the day of the survey. The overall prevalence of HAI was 1.7% and urinary tract and surgical wounds were the most frequent sites (each four patients, 26.7%). In only eight (53.3%) of the fifteen HAI detected, had a microbiological examination been requested and the only two positive culture results involved Pseudomonas aeruginosa (surgical site) and Escherichia coli (urinary tract). Results of multiple logistic regression analysis indicated that HAI differed significantly in prevalence between age groups, ward, and was higher in patients with urinary catheters and in those receiving antibiotics.