Résumé : Two unrelated children with congenital central hypoventilation syndrome (CCHS-Ondine syndrome) and long segment Hirschsprung disease are reported. Patient 1, a girl, is still alive at 3 years. Patient 2, a boy, died of viral pneumonia at 5.5 years. Continuous mechanical ventilation was necessary for months and those children could never be weaned from the respirator during sleep. Seventeen cases of this complex neurocristopathy are reviewed. Only six children (including our cases) survived beyond 2 years of age. Hypotonia, delay in developmental milestones or epilepsy were frequently observed. Ventilator dependency does not improve with time. Multifocal congenital neuroblastoma occurred in two children. Aetiology is unknown. © 1993 Springer-Verlag.