423 cases were underwent surgical treatment for herniated lumbar intervertebral disc during 12 years, and for these cases clinical analysis was done. The result were obtained as follows: 1. Among 423 surgically treated patients 20 are teenagers and male to female ratio was 309 (73.0%) to 114 (27.0%). 184 cases (43.2%) had a definite trauma histories, the types of injuries were lifting weight, direct trauma and slip down in order of frequency. 2. The teenagers had more severe tension sign and stiff back, while neurological dificits were less common in teenagers (45%) than the one in adult(55.2%). Average interval between the onset of clinical symptoms and time of operation were 3.4 months. 3. The definite discal rupture was found in 292 cases (69.0%) and the annular discal bulging were faund in 89 cases (21.0%). The most common site of lesions were between L 4-5 vertebrae (76.8%) and the next between L5-51 and L3-4 vertebrae. 4. The majority of surgically removed discs showed degenerative changes histopathologically. 5. Intervertebral discal space changes on X-ray after surgery were the narrowing of space, eburnation of end plate, spur formation and segmental instability, etc. 6. In this series of disc surgery were persistent backache, tingling and/or numbness in the leg, stiffback and limited S.L.R., etc., and the post-operative complications were subcutaneous hematoma, soft tissue infection, drop foot and diskitis, etc..