Background/Aim Children on chronic noninvasive ventilation are at risk for nonelective hospitalizations, mainly for acute infections. This study examined the prevalence of hypercapnia in children on chronic ventilatory support during an acute admission. Methods This retrospective study included children aged 0 to 18 years who regularly used bilevel positive airway pressure or continuous positive airway pressure at home, and who were diagnosed with an acute infection, and were hospitalized at the pediatrics department or pediatric intensive care unit. Capillary blood gas analysis and parameters of the built‐in software of the home ventilator were recorded. Results Among the 43 cases included, hypercapnia was prevalent in 23% with a mean partial pressure of carbon dioxide of 51.7 ± 6.4 mm  Hg. These children also had lower oxygen saturation levels. The respiratory rate 48 hours before admission was significantly higher in the hypercapnic group and the volume guarantee mode was less frequently used in the hypercapnic group. Conclusion Approximately, a quarter of the cases of chronic home ventilation experience hypercapnia during an acute infection. Our data warrant a prospective study on the monitoring of respiratory rate in patients with chronic respiratory insufficiency as an indicator for hospitalizations with hypercapnia; we also recommend the use of volume guarantee mode of ventilation to prevent hypercapnia.