Background: Children suffering from COVID-19 constitute about 10% of the entire population infected with the virus. In most of them, we observe asymptomatic or mild courses; however, about 1% of affected children require a stay in a paediatric intensive care unit (PICU) due to the course of the disease becoming severely life-threatening. The risk of respiratory failure, as with adults, is associated with the coexistence of concomitant diseases. The aim of our study was to analyse patients admitted to PICUs due to the severe course of their SARS-CoV-2 infection. We studied epidemiological and laboratory parameters, as well as the endpoint (survival or death). Methods: A retrospective multi-centre study, the analysis covered all children with a confirmed diagnosis of SARS-CoV-2 virus infection who were admitted to PICUs in the period from November 2020 to August 2021. We studied epidemiological and laboratory parameters, as well as the endpoint (survival or death). Results: The study analysed 45 patients (0.075% of all children hospitalised in Poland due to COVID-19 at that time). Mortality calculated in the entire study group was 40% (n= 18). Statistically significant differences between the compared groups (survived and died) concerned the parameters of the respiratory system. Lung Injury Score and the Paediatric Sequential Organ Failure Assessment were used. A significant correlation between disease severity and the patient’s prognosis was shown by the liver function parameter AST (p= 0.028). During the analysis of patients requiring mechanical ventilation and assuming survival as the primary outcome, a significantly higher oxygen index on the first day of hospitalisation, lower pSOFA scores and lower AST levels (p: 0.007; 0.043; 0.020; 0.005; 0.039, respectively) were found. Conclusions: As with adults, children with comorbidities are most frequently at risk of severe SARS-CoV-2 infection. Increasing symptoms of respiratory failure, the need for mechanical ventilation and persistently high values of aspartate aminotransferase are indicators of poor prognosis.