Five male military recruits were studied for evidence of immunologic deficiencies. Four had recovered recently from a first-episode meningococcal meningitis and one presented with recurrent meningococcemia. A selective decrease in IgG and IgA was found in one of the first-episode patients and a selective IgG2 subclass deficiency in the recurrent case. No complement abnormalities were detected, however, in any of the five cases. These results present further proof of the crucial role of immunoglobulins in the defense against N. meningitidis and they stress the necessity of a thorough examination of humoral immunity before military career enlistment.