Writing about a case of post-operative diaphragmatic bilateral palsy (bilateral thoracotomies for oesocoloplasty and oesophagectomy necessited by a caustic oesophagitis) on a 8 years old boy, palsy which was cured 6 months after, the authors tell about causes, prognostic and treatment of diaphragmatic palsies. In that observation, treatment consisted essentially in artificial ventilation for months and a half, and on intensive kinesitherapy.