The objective of this study was to evaluate the different causes of extubation failure and the consequent mortality rates in a pediatric population after cardiac surgery. We studied 184 consecutive patients with a median age of 9 months (range, 0–165). In 158 patients, extubation was successful (group A). Nine patients were reintubated for upper airway obstruction and finally extubated successfully (group B). Seventeen patients were reintubated for cardiorespiratory failure, finally leading to death in 11 of 17 patients (65%) (group C). Group B patients were younger and had a longer intubation period compared to group A patients. Group C patients had more reoperations (30% vs 4% in group A patients, p < 0.001), a lower PaO₂ on admission at the intensive care unit as well as just prior to extubation, a lower base deficit before extubation, and needed more inotropic support during their stay in the intensive care unit. We conclude that extubation failure after pediatric cardiac surgery due to cardiorespiratory failure is a bad prognostic sign. Patients with high inotropic support and a low PaO₂ prior to extubation are especially at risk and probably need careful evaluation before final extubation.