An epidemic of adenovirus 7a in our neonatal intensive care nursery and intermediate care nursery in July and August 1987 caused the death of two patients. Significant symptomatic infection possibly due to the virus occurred in nine patients, ten staff, and three parents, of whom three patients, three staff, and one parent were positive by culture. As a direct consequence of the outbreak, 58 staff days of work were lost; the intensive care nursery had to be closed to admissions for 19 days and the intermediate care nursery for 14 days. Seventeen newborns were transferred to other hospitals and four mothers were sent elsewhere for delivery. Control measures, which included cohorting of patients, use of gloves, gowns and goggles, and exclusion of symptomatic staff from the unit, appeared effective. Rapid immunofluorescence testing of virological specimens was of little use in monitoring the outbreak, largely because of poor specimen quality. This outbreak further underlines the ease of transmission and high morbidity of neonatal adenovirus infection.