Cytomegalovirus (CMV) infection is a serious complication of paediatric hematopoietic stem cell transplant (HSCT). To date, antiviral therapy has been the mainstay of prophylaxis, with conflicting results regarding benefits of CMV-specific immunoglobulins (CMV-Ig). After introducing prophylactic CMV-Ig for HSCT recipients at risk (seropositive recipient and/or donor), we conducted a single center retrospective study comparing incidence and severity of CMV infection with and without CMV-Ig. We identified 49 ‘at risk’ recipients from 76 consecutive HSCTs over 3.5 years: in addition to standard antiviral prophylaxis, 10 patients received CMV-Ig and 39 did not. There was no significant difference in donor type, cell source, conditioning or CMV status between the groups. We observed a trend towards lower incidence of CMV reactivation with CMV-Ig (30%) vs without (38.4%). No patient who received CMV-Ig developed symptomatic or lethal infection. Duration of infection appeared shorter (21 (+/-7) vs 51.4 (+/- 55) days) and peak titers lower (4 578 (+/- 4 788) vs 24 131 (+/- 49 257)) with CMV-Ig. No adverse events were noted. The statistical significance of results is limited by the small sample size. These data raise interest in prophylactic CMV-Ig as a safe way of potentially reducing severity and duration of CMV reactivation in HSCT.