Mediastinoscopy allows mediastinal examination through a cervical pathway. 17 mediastinoscopies were performed on 15 children with lymphomas (5 Hodgkin disease, 10 non Hodgkin malignant lymphomas). The diagnosis was assessed by mediastinoscopy on 10 patients which had only an abnormal mediastinal opacity and were free from extrathoracic localisation. This endoscopy was done on 5 children associated with a staging laparotomy to establish a prognosis and to investigate the spread of the disease before or during treatment. Diagnosis was obtained in 14 of the 15 patients. No surgical complications was observed. However, emergency care was necessary after two anaesthesical accidents in 2 children with malignant lymphomas. Mediastinoscopy is unfrequently required in children. Although in non surgical disease such as lymphomas, it may avoid an unnecessary thoracotomy and be repeated without damage.