PURPOSE: Juvenile dermatomyositis (JDM) is a common inflammatory myopathy in childhood. However, the diagnosis is often delayed because it frequently present with non-specific symptoms. In addition, there are conflicting opinions about the prognostic factors of JDM. The aim of this study is to delineate the initial clinical symptoms and prognostic factors of JDM. METHODS: We retrospectively reviewed the medical records of 15 patients who were diagnosed as JDM, in Samsung medical center between Dec 1994 and Aug 2011. RESULTS: We enrolled 15 patients (M:F=9:6). Among the 14 patients who were followed-up for more than six months, six patients were included in remission group, five in partial remission group, and the other three in non-remission group. The initial symptoms were skin lesions (80.0%), muscle weakness (53.3%), and pain of joint or muscle (46.7%). The interval between initial symptoms and clinical diagnosis was mean 0.4 (0.1-2.4) years. Nine patients (60%) were taken more than two months for diagnosis. The symptoms at diagnosis were motor weakness and skin rash in all patients, myalgia or arthralgia in 12 (75%) patients. The mood changes such as depression, irritability, easy fatigability were noted in 10 (66.7%) patients. There were no significant prognostic factors. CONCLUSION: Although JDM may initially present with nonspecific symptoms in children, it should be suspected in case of acute progressive motor weakness with symmetric skin rash and mood change. About three quarters of the patients were under control with treatment and there were no significant prognostic factors in this study.