The Microbiology Laboratory of São Paulo Hospital detected a increased number of contaminated urine samples, in the period from January to August, in 1988. It was observed that the problem was an incorrect technic in collecting those samples. So, in order to train the nursing staff, it was elaborated a study program by the nurses of Nursing Study Center, Infection Control Committee, and Laboratory. After this program the rate of contaminated samples had an important reduction, meanly in pediatrics wards. The authors concluded that the continuing education improves nursing practives in hospital and gives professional motivation to the staff