Introduction: Primary infection by the Epstein Barr Virus (EBV) is usually asymptomatic, but it is associated with infectious mononucleosis in a third of the cases, with potentially fatal complications in at least 1% of the patients. The clinical course of the disease varies according to the cohort studied, which delays its diagnosis. A descriptive observational study was carried out to perform the sociodemographic and clinical characterization of EBV infection in pediatric patients at the Colsubsidio Children's Clinic during 2015-2019. Methodology: Patients with positive Ag-VCA IgM were identified as a diagnosis of acute EBV infection. The sociodemographic, clinical and paraclinical characteristics of each patient were evaluated for their subsequent descriptive analysis. Results: 91 patients with active EBV infection were found with a median age of 8.15 years. The most affected group was preschool children. Fever was found in 91.2%, pharyngitis in 58.2%, cervical lymphadenopathy in 64.8%, splenomegaly and hepatomegaly in 34.5% and 27.2% of the patients. Leukocytosis was present in 45.1% with a predominance of lymphocytes in 61.5%, presence of atypical lymphocytes in 28.5% and monocytosis in 90.1% of the patients. Transaminases elevated in 49.1% (ALT) and 54.2% (AST). Complications occur in 20.9% of patients. The median hospitalization was 7 days. Conclusions: This study indicates the need for a greater diagnostic suspicion of EBV infection in the population studied. Additional studies are suggested to correlate the results found.