Nosocomial infections over an 11 years period were monitored prospectively in a district hospital. A total of nosocomial infections among 162.197 patients discharged from 1980-1990 were analyzed. The incidence rate of nosocomial infections was 3.6%. The predominant isolates were Escherichia coli and Staphylococcus aureus (11%). The highest rates of S. aureus infections were established in wound infections and skin and mucosal infections at surgery, gynaecology and paediatrics departments. The number of multiply resistant S. aureus strains has decreased and those of sensitive isolates has increased. 72% of 652 S. aureus isolates have been typed by phage typing and biotyping. Statistical analysis could not establish a significant relationship between phage patterns and nosocomial infections. The spectrum of phage patterns of these nosocomial strains was the same as those of the endogenous colonization of men. Nosocomial outbreaks could not been realized.