The control of nosocomial infection in a pediatric intensive care unit is important not only because of the serious nature of the patient's condition, but also because of the greater staff-patient contact and inevitable crowding of patients, staff, and equipment. In order to control the spread of nosocomial infection, the modes of transmission and the principles of infection control must be understood. Each patient with an infectious disease must be considered to be a potential source of nosocomial disease, and measures of infection control must be individualized for the infectious disease and for the level of intensive care required. The infection control committee of the hospital is an excellent source of advice in formulating care plans. Although compromises will inevitable be made between the ideals of infection control and intensive care needs, certain principles must be followed, the most important of which is proper handwashing between contacts and with patients.