Introduction: Congenital diaphragmatic hernia is often detected during the prenatal or neonatal period by severe respiratory symptoms. Late-presenting congenital diaphragmatic hernia is uncommon entity resulting in frequent misdiagnosis and inappropriate treatment. Case Report: We report the case of a left congenital diaphragmatic hernia revealed by an inaugural diabetic ketoacidosis in a 9-year-old girl. She has presented progressive weight loss without loss of appetite associated with polyuro-polydipsia, then epigastric pain with vomiting. Blood glucose was 3.2 g/L, ketonuria and 2+ glycosuria. Despite a well-conducted treatment, there was persistence of dyspnea. Chest X-ray and chest CT-scan confirmed the presence of a left diaphragmatic hernia. Evolution was marked by the death of the child on day 2 post-operative from a multivisceral failure. Conclusion: Clinical and radiological signs of congenital diaphragmatic hernia after the neonatal period may be difficult to interpret and may result in delayed diagnosis, erroneous treatment and potentially fatal outcome.