A prospective study of nosocomial infections in a nursery was undertaken in the Hospital of University of Paraná. Infections were identified during a 2 year period from August 1987 to July 1989 with a monthly analysis of prevalence site and agents responsible for nosocomial infections. The biannual mean was 30%. Staphylococcus aureus was the most commonly isolated pathogen. The most common site of nosocomial infections was muco-cutaneous. Educational measures were the most important factor in reduction of nosocomial infection rates.