We monitored 133 high-risk allo-SCT recipients for 6 months after transplant for EBV reactivation by quantitative real-time PCR. Rituximab was given as pre-emptive therapy for viremia >1000 copies/mL. The 1-year cumulative incidence of EBV reactivation was 29.4% (95% confidence interval (CI): 18-40) in patients monitored due to initial high-risk characteristics (n=93) and 31.8% (95% CI: 19.7-44) in those followed because of the development of refractory GVHD (n=40). Overall response rate to Rituximab was 83%. Nine patients (9.6%) developed post-transplant lymphoproliferative disorder (PTLD) at a median of +62 days after SCT. Eight of them showed a concomitant CMV reactivation. Second SCT was the only risk factor associated with EBV infection and PTLD in multivariate analysis (hazard ratio (HR) 2.6 (95% CI: 1.1-6.4; P=0.04) and HR 6.4 (95%CI: 1.3-32; P=0.02)). The development of EBV reactivation was not associated with non-relapse mortality or OS (P=0.97 and P=0.84, respectively).