The emergence of meningococcal strains with reduced susceptibility to penicillin has been reported in several countries during the past two decades, but not in Taiwan. We report a case of meningococcal meningitis with intermediate resistance to penicillin. A 20-year-old male soldier complained of chills, fever, and headache for 2 days, followed by drowsiness. Physical examination revealed er erythema of the pharynx, stiff neck, erythematous maculopapules, and petechiae over the trunk and four limbs including palms and soles. Analysis of the cerebrospinal fluid (CSF) showed a white blood cell count of 9.06 x 10(6)/L, a glucose concentration of 0.165 mmol/L, and a protein concentration of 7.85 g/L. CSF Culture yielded Neisseria meningitidis, serogroup B. The minimum inhibitory concentration of penicillin was determined using an E-test (0.125 mug/mL); there was no beta -lactamase production. He recovered after high-dose penicillin G treatment with six doses of 24 million units per clay for 11 days. The emergence of penicillin resistance in X. meningitidis in Taiwan requires surveillance. high-close penicillin may be successful in treating penicillin-insensitive meningococcal meningitis. Alternative,e treatment with third-generation cephalosporins should be considered if poor response to penicillin is encountered.