Respiratory syncytial virus (RSV) respiratory infections are very common during infancy and account for the majority of hospitalizations during the fall and winter seasons. Patients vary in the severity of their illnesses, with most hospitalized patients needing oxygen and intravenous fluids. The objective of this study was to assess in hospitalized patients the severity of the disease in relation to age. We compared children who were <90 days old with children who were >90 days old for the duration of oxygen therapy, maximum oxygen concentration used, duration of stay and duration of intravenous fluids. We conducted a retrospective case review of national children <2 years admitted to the pediatric ward at Sheikh Khalifa Medical City with RSV proven bronchiolitis/pneumonia over a 3-month period from 1 September to 30 November 2001. Morbidity for group 1 (birth–90 days) and group 2 (91 days–2 years) was compared by the Mann–Whitney U-test using duration of oxygen therapy, maximum oxygen concentration used, duration of stay and duration of intravenous fluids. Multiple regression for duration of oxygen therapy was tested using the following risk factors as predictors: age group (1 or 2), previous ventilation, bronchopulmonary dysplasia (BPD) and prematurity. A total of 89 patients were admitted during this period. The mean age (SD) of group 1 (n=28) and group 2 (n=61) was 46.35 (25.57) days and 275.67 (156.79) days, respectively. The only statistically significant difference using the Mann–Whitney U-test was detected for duration of oxygen between the groups (p=0.002). Using multiple regression, only age group acted as a predictor for duration of oxygen therapy (p < 0.001). This implies that the youngest children, group 1, are at a risk for prolonged oxygen therapy. Four patients from group 1 were admitted to the intensive care unit, of which two received ventilatory support. RSV respiratory infections affect infants <3 months old in a more severe form than older infants. Even though overall duration of stay was similar for both groups, young infants who in fact did require oxygen had a more protracted and severe illness compared with the older infants. This was evidenced by their longer duration of oxygen and more frequent need to be managed in the intensive care unit.