• An outbreak of nosocomial varicella occurred in the neonatal intensive care unit of a west Texas hospital in 1982. Two health care workers and two infants were infected. The two infants acquired varicella following intimate exposures, although their mothers were shown to be seropositive. One of these infants had varicella-zoster antibody when exposed, received varicella-zoster immune globulin, and still had chickenpox develop. Thus, the presence of varicella-zoster antibody may not prevent infection in infants.