Background: The incidence of coronavirus disease 2019 (COVID-19) is still increasing rapidly, but little is known about the prevalence and characteristics of fatal cases in children in Indonesia. This study aimed to describe the characteristics of children with COVID-19 with fatal outcomes in a tertiary referral hospital in Indonesia. Methods: This cross-sectional study used data collected from the medical records of patients with COVID-19 admitted to Dr. Cipto Mangunkusumo Hospital, Jakarta, Indonesia from March to October 2020. Results: During the study period, 490 patients were admitted and diagnosed with suspected and probable COVID-19. Of these patients, 50 (10.2%) were confirmed to have COVID-19, and 20 (40%) had a fatal outcome. The fatality rate was higher in patients aged ≥10 years, categorized with severe disease upon admission, PaO2/FiO2 ratio ≤300 mmHg and chronic underlying diseases. The most common clinical manifestations were generalized symptoms, while acute respiratory distress syndrome (8/20) and septic shock (7/20) were the two most common causes of death. Increased procalcitonin, D-dimer, lactate dehydrogenase and presepsin levels were found in all fatal cases. One patient met the criteria of multisystem inflammatory syndrome in children. Conclusion: Our work highlights the high mortality rate in paediatric patients with positive SARS-CoV-2 polymerase chain reaction test. These findings might be related to or co-incided with COVID-19 infection. Further studies are needed to improve understanding of the role of severe acute respiratory syndrome coronavirus-2 in elaborating the mechanisms leading to death in children with comorbidities.