Failed lumbar disc surgery (FLDS) is a serious complication of lumbar disc surgery and as persistent or recurrent back pain and radiating pain after low back surgery, the incidence of FLDS has been estimated to be approximately 6 percent to 30 percent but most observers would consider 15 percent. We report the etiology, treatment and prospective results of 44 FLDS patients, 38 patients of whom had performed reoperaion (9 cases; decompression, 29 cases; decompression and fusion) and 6 patients were treated conservatively from Jan. 1980 to Dec. 1990 and results were as follows. 1. The most common causes of FLDS were epidural fibrosis, spinal stenosis, recurrent disc herniation and new disc herniation. 2. The most common lesion site of FLDS was on L4-5 disc space. 3. CT & myelogram, MRI provided excellent images for diagnosis. 4. The clinical results were good in cases with the etiology of recurrent disc herniation, new disc herniation, wrong level and hematoma formation. 5. The clinical result were good in cases with the symptom of more than 6 months of pain free interval and sciatica predominating over LBP. 6. the success rate lumber disc surgery depended on patient selection, surgical technique and method of assessing the outcome.