On September 27, 2012, the New York City (NYC) Department of Health and Mental Hygiene (DOHMH) alerted health-care providers and the public about 12 cases of invasive serogroup C Neisseria meningitidis disease (SCMD) occurring in NYC since August 2010 among men who have sex with men (MSM). Cases were identified through existing mandatory notifiable disease reporting and classified according to the Council of State and Territorial Epidemiologists case definitions. By December 31, 2012, a total of 18 cases had been identified among MSM. For 2012, the incidence rate of invasive meningococcal disease among MSM aged 18-64 years was 12.6 per 100,000 persons, compared with 0.16 among non-MSM males aged 18-64 years. MSM and non-MSM population denominators were obtained from the 2010 NYC Community Health Survey a telephone-based survey of approximately 10,000 NYC residents.