Cytomegalovirus is common in adult recipients (prevalence of 40–90%). Children are typically seronegative but immunosuppression may prone to primary-infection or viral reactivation, with potentially severe consequences. CMV infection incidence in pediatric kidney transplant recipients has seldom been investigated. The aim of our study was to evaluate the incidence and timing of CMV infection during the first year after renal transplantation. We assembled a retrospective cohort of 136 children who had received a kidney transplant between 2003 and 2014 with a year follow-up. The patients were classified regarding CMV infection as high risk (D+/R−), intermediate risk (R+) or low risk (D−/R−). CMV infection was defined by the viral replication remaining asymptomatic whereas CMV disease concerned viral replication with clinical and/or biological symptoms. Oral valganciclovir was used as prophylaxis for high-risk recipients. A total of 38 patients (27.9%) developed CMV infection, 13 (40.6%) of the 32 D+/R−, 24 (45.3%) of the 53 R+ and 1 (2.0%) of the 51 D−/R−. Of these 38 infected patients, 10 developed tissue-invasive disease. During the first year after kidney transplantation, 27.9% of recipients developed CMV infection. This study confirms the influence of donor and recipient CMV status on infection propensity and highlights the importance of adequate follow-up for intermediate risk patients.