The natural history and clinical significance of posttransplant Epstein-Barr virus (EBV) infection remain largely unknown. The aims of this study are to describe the incidence, risk factors and consequences of EBV infection after kidney transplantation. A total of 383 consecutive patients having received a kidney transplant between January 2002 and December 2010 were included. EBV polymerase chain reaction (PCR) was performed every 2 weeks for 3 months, and every 4 weeks for the next 9 months. A total of 155 of the 383 patients (40%) had at least one positive viremia during the first year posttransplant. The median time to viremia was day 31 posttransplant (14–329). A total of 73 (47%) had EBV viremia > 103 log and 23 (15%) had positive viremia for more than 6 months. EBV D+/R− patients (12/18 (67%) versus 143/365 (39%), p = 0.02) and those having received antithymocyte globulins (ATG) (54% vs. 35%; p<0.001) were more likely to develop EBV infection. EBV infection (hazard ratio [HR], 3.03; 95% confidence interval [CI], 1.72–8.29; p = 0.01) was associated with the occurrence of opportunistic infections. A positive EBV PCR during the first 6 months posttransplant was associated with graft loss (HR, 3.04; 95% CI, 1.36–6.79; p = 0.014). EBV reactivation is frequent after transplantation and reflects overimmunosuppression. Prospective studies should examine the association between EBV and graft loss.