For the purpose of evaluating the oral health status and assessing the resultant dental treatment needs in adolescents, 2,062 adolescents with age of 14-17 years attending in middle and high schools in Yangsan City were surveyed by clinical examination and questionnaires. The obtained results were as follows: 1. By the dental caries examination with WHO criteria, 4.15 of DMFT index and 66.7% of treatment need were revealed. 2. Dental erosion assessed by VEDE system were shown as 42.7% of prevalence and 27.8% of treatment needs. 3. MIH examination by EAPD criteria showed 14.7% of both prevalence and treatment need. 4. Malocclusion, assessed by Occlusal index, were shown as: good occlusion in 67.8%, no need for treatment 19.7%, slight need for treatment 6.8%, definite need for treatment 4.5% and worst occlusion in 1.1%. Average treatment need was 12.5%. 5. Periodontal disease by CPITN was assessed as 71.2% of both prevalence and treatment need. 6. Temporomandibular disorders, assessed by Helkimo''s anamestic index, were revealed as : no symptom in 67.1%, mild symptom in 13.4%, and severe symptom in 19.5%. Their treatment need was 20.6%. Periodontal diseases take the highest rank in treatment need, followed by dental caries, dental erosion, MIH, TMD and malocclusion in order. By the results of this study, overall status of adolescents'' oral health and dental treatment needs were understood. These might hopefully provide fundamental data and contribute to the establishing promotion project of adolescent oral health in Korea.