Purpose: We report sharp rise of incidence of mumps meningitis at our institute in the past year and described the clinical manifestations, laboratory findings, and complications. Methods: This is a retrospective study involving 18 patients with mumps meningitis at Eulji University Hospital between July 2012 to June 2013. They were diagnosed by definite parotid gland swelling and leukocytosis in CSF study. Results: We identified 17 boys and 1 girl clearly showing male predominance. The age group involved was 12 to 17 years, mean being 15.2 years. All the 18 patients were received two dose of mumps vaccine according to the National Immunization Schedule. The initial clinical features included fever(100%), nausea or vomiting(100%), headache(100%), unilateral parotitis(28%), bilateral parotitis(72%). The duration of CNS symptoms onset was 1 to 7 days, mean being 4.6 days. The investigations included raised serum amylase(88%). Initial CSF examination showed lymphocytic predominance with cell count range between 5 and 2,595 /uL, mean being 362. Mumps virus specific IgM positivity was 6 of 14 (43%) in serum and 4 of 17 (24%) in CSF. The total duration of illness including hospitalization was 9 to 15 days, mean being 10.8 days. There was no serious neurologic deficit but 6 of 18 (33%) complained mild headache or dizziness after discharge. It caused delay in back-to-work. Conclusion: It is worthy of notice that recent outbreak of mumps among adolescents are more complicated. We need to be more aggressive about prevention of mumps outbreak to bring on substantial socioeconomic loss.