From July through October 1991, an outbreak of hepatitis A virus (HAV) infection involving 26 hospital staff, inpatients and household contacts occurred in a pediatric hospital. All ill staff members had cared for one inpatient who had profuse diarrhea with gross fecal contamination of the environment, negative HAV serology and idiopathic immunodeficiency. HAV infection in this patient was later confirmed by polymerase chain reaction. Among hospital staff HAV attack rates were highest in nursing personnel (15%). A retrospective cohort study of nurses found that the risk of infection was greatest in those who handled the source patient's soiled bed pad (relative risk, 6.7; 95% confidence intervals, 1.6, 27.8), diaper (relative risk, 5.4; 95% confidence intervals, 0.8, 39.2) or gown (relative risk, 2.9; 95% confidence intervals, 1.1, 7.8). Glove use during these activities was not associated with a lower risk of infection, possibly because of gross environmental contamination or less use than reported. This situation was unusual because the patient was HAV-infected but had negative serology, probably because of immunodeficiency. In situations of potentially extensive environmental contamination, such as with a diapered or incontinent patient with suspected or confirmed hepatitis A, careful attention to frequent handwashing is an essential protective measure; in addition strict glove use whenever entering the patient's room should be followed to provide additional protection.