Introduction: Diaphragmatic relaxation is an infrequent condition characterized by a permanent elevation of all or part of an hemidiaphragm which maintains its insertions on the ribs and which does not have continuous solutions but a reduced thickness. Presentation of case: We studied a 65 years old male patient with mild dyspnea and chest pain occurred during the last 12 months after moderate efforts. He underwent a contrast enhanced CT thorax scan that showed a left diaphragmatic relaxation with the transposition in the cranial sense of the hypochondriac abdominal organs associate with an ipsilateral subtotal atelectasia. A laparoscopic plication of the diaphragm was performed to repair the congenital defect. Discussion: The relaxatio diaphragmatica is probably caused by a congenital defect, but there are also idiopathic causes or cases of acquired relaxation due to phrenic nerve damage because of neoformations, traumas, thoracic and cardiac surgery. In cases of asymptomatic relaxatio nothing is necessary, but in symptomatic cases it is possible the plication of the diaphragm with a remission of symptoms. Conclusion: The plication can be performed through thoracotomy or laparotomy and recently also in thoracoscopy or laparoscopy. In our experience the laparoscopic repair of the relaxatio was accomplished successfully with a left pneumothorax compatible with the intervention, but the operative strategy should be always individualized with attention on diagnosis, patient characteristics, availability of resources and experience of surgical team.