The complement system is important in the generation of the normal inflammatory response and in host defense against systemic infection. Therefore, inherited or acquired deficiency of complement is associated with an increased frequency of infection. As a major effector of the complement cascade, the membrane attack complex is responsible for direct complement dependent serum bactericidal activity. Especially late complement component deficiency has a markedly increased risk of meningococcal infection and is subject to recurrent infection. We experienced a patient who had recurrent meningococcal meningitis and septicemia. The patient was 13-years old boy and he had a recurrent episode after 20 months. At second admission, we examined complement level and C7 deficiency was confirmed. He was treated without complication. We report a case of deficiency of C7 with recurrent meningococcal meningitis and septicemia.