Objective: characterize clinically and epidemiologically pediatric patients diagnosed with leukemia of acute presentation confirmed by flow cytometry from a hospital in Medellín, Colombia between 2012-2017. Methods: A retrospective analytical study was carried out, which included pediatric patients diagnosed with acute leukemia confirmed by flow cytometry at a hospital in Medellín. A non-probability sampling of consecutive cases was carried out. The information was secondary, through medical records. The analysis was carried out through the IBM SPSS version 25 program. This work had the ethical approval of the institution. Results: 54 pediatric patients were included; Regarding sociodemographic characteristics, it was found that 57.4% (31) were male, 48.1% (26) were <5 years old, 27.8% (15) between 5 and 9 years old and 24.1% (13) were ≥ 10 years old. Regarding the personal history, the main one was the presentation of acute infections with lymphocytosis with 18.5%; 9.3% of the patients had a family history of leukemia. 74.1% presented a diagnosis of lymphoma/lymphoblastic leukemia of B cells. 29.6% of the patients were admitted to the Intensive Care Unit, 59.3% had remission and 22.2% of the population died. Conclusion: The pediatric population represents a high percentage of diagnoses of hematologic malignancies, although their diagnosis and management have state-of-the-art technological aids, it's still a disease with high mortality.