The authors have experienced 91 cases of herniated intervertebral disc, (HIVD) of lumbar spine which were surgically treated with classical approach (partial laminectomy and discectomy) and followd up for more than 1 year since September, 1983. Summary of clinial analysis upon these cases are as follows. l. Operations were performed in 91 cases (35.4 % ) among 257 cases of admitted HIVD's, 50 cases (54.9%) of which were male and 41 cases (45.1%) were female. Age distribution was ranged from 14 to 67 years, 34 years in average. 2. The sites of disc herniation were 2 cases (2.2%) in L3-4, 67 cases (73.6%) in L4-5, and 21 cases (23.1%) in L5-Sl intervertebral level. Nagative exploration was in 1 case (1.1%). 3. At 2 years and 6 months follow up in average, the results were excellent in 32 cases (35.2% ), good in 49 cases (53.8%), fair in 4 cases (4.4%) and failure in 6 cases (6.6%) according to Naylor's, assessment scheme. The excellent and good results comprised 89.0% of the total if they are summed up. 4. Failed back syndrome was diagnsed in 10 cases, 6 cases of which were reoperated. Findings at reoperation of the 6 cases were recurrence of herniation in 4 cases, incomplete removal of ruptured fragment in 1 case and epidural fibrosis in 1 case. From the above observations, the authors are convinced that there is still sound ground for so called classical surgery for HIVD if indication and technical details are strictly clung to.