• An outbreak of hepatitis A involving 15 nurses, two premature infants, and the mother of one infant occurred in an intensive care nursery. The infants became infected after receiving blood transfusions from a donor who shortly thereafter experienced symptoms compatible with hepatitis A and was later found to have serologic evidence of acute hepatitis A. Hepatitis was not suspected clinically in the infants but was documented serologically. One of the infants had an ileostomy with liquid intestinal drainage. Her mother and most, if not all, of the nurses acquired hepatitis from this infant. All 15 nurses had contact with this infant, whereas only four nurses had contact with the second infant. The amount of contact nurses had with this infant clearly was related to their risk of infection. Nurses not actually assigned to this infant but who reported some contact had a significantly lower attack rate than those assigned to the infant. Among assigned nurses, those assigned to more than one shift had 4.7 times the risk of acquiring hepatitis than those assigned to one shift only. No specific nursing techniques or personal habits were documented as being significant risk factors in the infected group of nurses.