Introduction Although the incidence of tuberculosis in Korea has decreased, it is still higher than other developed country. It is necessary to keep a tight rein on tuberculosis control. The aim of this study is to analyze the clinical features, diagnosis and treatment of tuberculosis. Method The records of all Mycobacterium tuberculosis infected children and adolescents younger than 19 years of age cared for at the Ewha Mokdong Hospital between July 2008 and June 2013, were reviewed. These records contain information on patient demographics, history of exposure, diagnosis, treatment and outcome. Result Forty two adolescents and children were treated for tuberculosis during a five-year period. Ages of the patients ranged from 22 months to 18 years and the median age is 14 years old. They showed male predominance of 1.5 times. Thirty-five (83.3%) were diagnosed with intra-thoracic tuberculosis and 7 (16.7%) with extra-thoracic alone. One patient had disseminated tuberculosis. Route of infection was not confirmed in 24 patients and 16 had a history of recent household contact with a tuberculosis case. 7 patients were diagnosed through the medical examinations with no clinical symptoms. One of our patients and two adult contacts were treated for tuberculosis as a result of active contact tracing after the cases were diagnosed. Coughing (25, 71.4%) was the most common presenting symptom and both upper lobes (21, 60.0%) were most frequently involved in pulmonary tuberculosis. Six patients had cavitary tuberculosis. Almost patients (35, 87.5%) had a positive tuberculin skin test; however, the rate of positive culture was low (29, 69.0%). Drug resistance to isoniazid was detected in one and multidrug resistance was detected in two. Adverse effects of anti-tuberculosis treatment were in 3 patients (hepatotoxicity and visual dimness). Although rib deformity and total occlusion of bronchus were reported as complication of tuberculosis, there was no fatal case. Discussion This study showed that pulmonary tuberculosis in adolescents and childhood has similar characteristics with tuberculosis in adults, which suggests the potential important role of these age group in community transmission. Focusing on active contact tracing among all household contacts of tuberculous cases may be helpful in early identification and controlling childhood disease.