• Micrococcic infections resulting from cross infection within hospitals may be the most serious current communicable disease problem. Micrococci are remarkably well adapted for cross infection in a hospital environment, remaining viable and even virulent in a dried state on dust or bedding. Any break in the skin, surgical or traumatic, including that made by intravenous catheters, appears to open the way for micrococcic invasion, and in infants invasion may take place through normal, intact skin. Hospitalacquired infections seem largely preventable, and the application of control measures including isolation of hosts and sterilization of vectors must be put into effect.