One hundred and twenty patients with symptomatic lumbar disc herniation were treated with automated percutaneous lumbar discectomy(APLD) from June 1988 to October 1989 in Seoul National University Hospital. Among them, 95 patients were followed up for more than 6 months. Number of male patients was 58 and female 37. Age ranged from 15 to 57 years with average 28 years. L4-L5 was the most commomly involved level comprising 80%, and 2 level involvement was 9%. Average duration of procedure was 38 minutes, and average amount of tissue aspirated was 5.2 grams and average hospital stay was 2.4 days. The average follw up was 10.8 months. Eighty seven percent of patients were satisfactory and 13% unsatisfactory and there was no major complication. There was no significant disc space narrowing in all the cases and the size of herniation revealed no significant change in all the patients, even the patient had a satisfactory result. APLD was compared with chemonucleolysis performed during 1988 in terms of clinical results, disc space narrowing on plain films and herniation size change on follw up CT. Chemonucleolysis also had satisfactory result in 89% with reduction of herniation size in 41% but induced significant disc space narrowing in 84%. Authors experienced some special cases, which are generally considered poor indication for percutaneous discectomy. Those were degenerative, calcified and possibly ruptured discs. Satisfactory results were obtained in 10 of 14 these patients.