In a prospective study, all patients admitted to a unit for convalescing newborns on an infant-toddler ward between January and April 1985 were tested every other day for rotavirus (RV) excretion by using an enzyme-linked immunosorbent assay. RNA electrophoresis of the RV strains identified in this population were analyzed to determine whether specific strains of virus were associated with infections in newborns. RV strains infecting older, symptomatic children from the infant-toddler ward were used for comparison. Among the 39 patients enrolled in the study, RV was detected in the stools of 13 (33%), 11 (86%) of whom were asymptomatic. Three different electropherotypes were seen among the newborns who were RV positive; these electropherotypes were identical to those identified in older children with community-acquired diarrhea and nosocomial-acquired diarrhea who were hospitalized on the infant-toddler ward during the same study period. Each of the three strains was first identified in the general ward and subsequently detected in the room with newborns within three to six days. We failed to identify a particular strain that exclusively infected newborns.