Retroperitoneoscopy is our preferred technique for renal surgery and is routinely performed for living donor nephrectomy. We report a case of a totally bisected left hemidiaphragm during left-sided retroperitoneoscopic donor nephrectomy. This was most likely caused when creating the retroperitoneal working space by balloon dilation. Because the cardiopulmonary situation of the patient remained stable, retroperitoneoscopic donor nephrectomy was performed with the standard technique. This report describes for the first time the retroperitoneoscopic reconstruction of a diaphragmatic injury.