Aseptic meningitis, an acute inflammatory process of the meninges, is characterized by pleocytosis and absence of microorganisms on Gram stain and routine bacterial culture of CSF, and commonly occurs in children. Although aseptic meningitis occurs sporadically all the year round, in areas of temperate climates as in Korea, most cases occur in summer and fall, and the large scale epidemics draw a great deal of social concerns. Among the various etiologies, enteroviruses are the causative agents in about 85% of all cases. Although the clinical course is self-limited in most instances, substantial morbidity and mortality may be observed in some cases. In dealing with the patients of suggestive aseptic meningitis, it is important to rule out the diseases that are fatal but treatable.