The aim of the present case report is to present the diagnostic and therapeutic challenge of intercostal incisional hernia. We report on a female patient with leftsided intercostal incisional hernia between the eleventh and twelfth rib due to preceding lumbar incision for tumor nephrectomy. Because of its infrequence, diagnosis was established late although simple clinical examination and ultrasound investigation displayed the hernia. At laparotomy, a 5x5 cm(2) fascial defect with a colonic sliding hernia was found. Hernia repair using permanent mesh reinforcement in the retromuscular position is described. Abdominal incisional hernia in the intercostal region is rare and therefore easily overlooked. As with other incisional hernias, the hernia repair using mesh implantation in the retromuscular region is technically feasible and represents the treatment of choice.