One hundred and one previously healthy patients Hospitalized with RSV LRI received either 1500 mg/kg of RSV-immune globulin (RSVIg) or albumin placebo(P) in a randomized, double blind placebo-controlled trial. Forty-six RSVIg and 52 P met all eligibility criteria. The two groups were similar in demographic factors. A higher proportion (46% vs 29%) of RSVIg (p=.07) had SaO2 ≤ 85% at entry than P. There was a trend toward more ICU care of or required mechanical ventilation at study entry in P. The mean RSV hospital stay was 5.52 ± 0.69 (SE) for P and 4.58 ± 0.40 days for RSVIg, a reduction of 17% (p=0.24). Additionally, there was an interaction between treatment group and entry respiratory score (p=0.09). Children with a modest respiratory illness did not receive any benefit from RSVIg therapy. Those with more severe illness (respiratory scores ≥ 2.5) had a 25% reduction (p=0.11) in hospital days. This resulted in an average of 1.6 days less hospital days than P. RSVIg reduced mean ICU stays by 41% (2.7 days p=0.06), and reduced mechanical ventilation days by 22% (p=0.45). Infusions appeared safe and generally well tolerated. We concluded that especially in sicker children RSVIg treatment may result in reduced hospital days, ICU stays, and fewer mechanical ventilation days. (Supported by MedImmune Pharm. Inc.).