Lumbar disc is degenerated after the age of 20 years when the growth and development is finished. With the degenerative process, rupture of the intervertebral disc into the spinal canal with nerve root compression would produce clinical picture of low back pain and sciatica. Herniated lumbar disc occured under the age of 19 years is rare. 544 operative cases of herniated lumbar disc was analysed at Department of Orthopedic Surgery, Yonsei University College of Medicine from Jan. 1982 to Dec. 1991. The result of the study are followed: 1. Herniated lumbar disc in adolescent was increasing. 2. Age distribution of adolescent group was from 11 to 19 years and mean age was 17.8 years old. 3. Among 544 patients, 77 patients were under 19 years old and 56 patients (72.7%) were male and 21 patients (27.3%) were female. 4. 42 patients (54.4%) had trauma history and 18 patients (42.9%) associated with sports activity. 5. Straight leg raising tests were positive in all 77 cases. 6. Sensory changes and motor weakness were present less than a half. 7. The most frequent level of herniation was L4-5 intervertebral disc space and more common in 1 level. 8. Operative result was excellent and good in all 77 cases. In conclusion, herniated lumbar disc in adolescent was increasing, more common in male, had more trauma history, more association with sports activity, more sensitive in straight leg raisig test, more common in L4-5 intervertebral space and one level, less common neurologic symptom and better operative result than in adult.