Background. COVID-19 is usually less severe and has lower case fatality in children than in adults. We aimed to characterize the clinical and radiological features of children and adolescents hospitalized with laboratory-confirmed SARS-CoV-2 infection and to evaluate the risk factors for COVID-19-related severity in the pediatric Mexican population. Methods. We did an analysis of all patients younger than 18 years who had quantitative RT-PCR-confirmed COVID-19, admitted to the National Pediatrics Institute, and described their clinical characteristics with the radiological findings at admission, related to the severity and clinical outcome. Results. A total of 129 patients had available data showing laboratory-confirmed SARS-CoV-2 infection and were included in the sample. Among these patients the most common signs were fever (82.2%), tachypnea (72.1%) and cough (71.3%). The most frequent radiological pattern that stood out was the interstitial pattern (66.7%). History of oncologic pathology (25.6%) was the most frequent past medical history. ESR was the only laboratory value significantly associated with severity (27.82  23.83 mm/hr). NSAIDs (93%), antibiotics (57.4%), and steroids (40.3%) were the most common medication given. The average hospitalization stay was 14.2 days, 21.7% of the total patients required transfer to the intensive care unit. At discharge, 20.2% required oxygen on an outpatient basis, and unfortunately 7.0% of the patients who were admitted to the institute for COVID-19 died. Conclusions. COVID-19 in children was associated with mild symptoms and good prognosis; ESR was the only laboratory value significantly associated with severity. Patients with hematologic/oncologic co-morbidities had severe presentations.