OBJECTIVE To describe the epidemiology and severity of illness of children hospitalized with respiratory syncytial virus (RSV) infection, including those who received palivizumab prophylaxis, at Royal University Hospital (RUH), Saskatoon and Regina General Hospital (RGH) from July 2002 to June 2005. METHODS Children hospitalized for ≥ 24 hours with laboratory-confirmed RSV infection were enrolled, and their health records were retrospectively reviewed for patient demographics and referral patterns, use of palivizumab prophylaxis, severity of infection (length of hospitalization, need for and duration of pediatric intensive care and mechanical ventilation) and outcome of infection. RESULTS A total of 590 children (324 males) were hospitalized over the three years. The median chronological age at admission was 5.3 months, and median hospital stay was 4.0 days. Gestational age at birth was ≥ 36 weeks in 82.4% of patients. RSV disease severity was mild to moderate in 478 patients (81.0%) and severe in 110 (18.6%). Thirty-nine patients (6.6%) required pediatric intensive care unit admission, for a median of 5.0 days. Twenty-two of these patients (56%) were mechanically ventilated for a median of 6.0 days. Two children died, not attributed to RSV infection. Twenty-two patients had received palivizumab prophylaxis before hospital admission, with 18 completing at least 2 of the monthly doses. Most of these children (17/22) had mild to moderate illness. CONCLUSIONS RSV causes significant morbidity in Saskatchewan, affecting predominantly term infants. The majority of illness is mild to moderate. Some patients who have received palivizumab may still develop significant RSV disease.