A personal computerised system was developed for the on-going assessment and monitoring of hospital infections. The system involves the computer processing of clinical analyses. It also selects and statistically processes the data from microbiological tests conducted on hospital patients and staff. The system makes it possible to monitor the microbiological situation of the hospital environment with particular reference to the air, surfaces, instruments and material. In this way it is possible to identify the outbreak of minor hospital epidemics and to monitor their evolution and spread.