Spondylolisthesis; occurs when a vertebral body is anteriorly displaced or `slipped` relative to the caudal vertebral body. Isthmic spondylolisthesis (IS) occurs as a result of a defect in the pars interarticularis due to acute or repetitive stress. The most important of the radiological examinations; lateral, anteroposterior and oblique standing radiographs of the lumbosacral junction. Many cases of IS are asymptomatic. However, the most common presenting symptom is low back pain, which can be mechanical in nature. Preoperative neurological and radiological evaluation is important in the selection of the treatment to be applied. Pars defect repair can be performed in patients who do not have neurologic deficits and radicular pain due to discal pathology. Inter-body fusion techniques to be added to posterior stabilization in IS increase the success of surgical results.