The restrictive measures required to face the recent outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may impact patterns of healthcare utilization. Our aim was to provide an insight into the change in the use of a pediatric emergency department (ED) during the SARS-CoV-2 pandemic. The medical records of the children seen in our pediatric ED during March and April 2020 were retrospectively reviewed. Consequently, these were compared to the medical records of 2018 and 2019 from the same time period and from other control periods (January–February 2019 and 2020, and July–August 2018 and 2019). The total number of ED visits declined by 73% from 2019 to 2020 (3051 vs 818). Significant variations were observed in the distribution of children between triage categories: the proportion of patients who was given a green-code showed a 0.59-fold decrease in comparison to 2019 (95% CI 0.5–0.69), while a relative increase in the proportion of yellow codes was observed (OR 1.46, 95% CI 1.2–1.78). Conclusion : Quarantine measures significantly impacted on the total number of patients and on the reasons for visiting them in our pediatric ED. This substantial decrease in pediatric care may either be due to lower rates of acute infections because of social distancing, or to parents’ or caregivers’ reticence to risk exposure to SARS-CoV-2 in a health-care setting. What is known: • A recent outbreak of a novel coronavirus responsible for a severe acute respiratory syndrome is spreading globally. • Restrictive measures may impact patterns of healthcare utilization, as observed in other previous outbreaks. What is new: • This study shows significant variations in the distribution of children among triage categories during the COVID-19 pandemic. • Discharge diagnosis was significantly different as well, in particular a relative increase in the proportion of children presenting with traumatic injuries and a decrease of viral infections were observed. Supplementary Information The online version contains supplementary material available at 10.1007/s00431-020-03909-9.