Ribavirin was approved in early 1986 for treatment of illness associated with respiratory syncytial virus (RSV) infection in hospitalized children; however, the value of its use remains controversial. This investigation was undertaken to describe ribavirin utilization and to evaluate the effectiveness of ribavirin in reducing the period of hospitalization. All children with laboratory-confirmed RSV infection, hospitalized over seven epidemic periods at a single institution, were identified. Characteristics from the medical records of the 768 children and their course of hospitalization were evaluated as determinants of treatment with ribavirin. Very young age as well as diagnoses of congenital heart disease, certain pulmonary conditions, and failure to thrive were all significantly related to increased likelihood of treatment. Children requiring intensive care were likely to be treated; however, the most critically ill children, those who required mechanical ventilation, were not treated. Although these results were in keeping with treatment guidelines for the use of ribavirin, actual utilization declined significantly over the course of the evaluation. The effect of ribavirin treatment on the duration of hospitalization among children with community-acquired infection was evaluated in a multivariate model, which controlled for the effects of underlying conditions, measures of illness severity, and epidemic year. This analysis failed to demonstrate a benefit for ribavirin in reducing length of stay; in fact, ribavirin treatment was significantly associated with prolonged hospitalization. It was not likely that the explanation for ribavirin's association with prolonged hospitalization was that the most seriously ill children were treated; however, it was not possible to determine whether this association was due to an adverse effect of treatment or resulted from a perceived need to complete the course of therapy.