We sought to identify population and subpopulation disparities in rates of HIV diagnosis and prevalence among black males 13 years and older in New York City. We used population-based data from the New York City HIV/AIDS surveillance registry and US Census 2000 to calculate HIV prevalence in 2006 and HIV diagnosis rates in 2007. Black males were the largest demographic group of new HIV diagnoses (n = 1,161, 33%) and persons living with HIV/AIDS in New York City (n = 24,294, 29%) and had the highest diagnosis rates (1.7 per 1,000 population) and prevalence (3.7%). Prevalence and diagnosis rates among black males were higher in higher-poverty neighborhoods than in lower-poverty neighborhoods (p < 0.01). However, very high prevalence (19.3%) was found among black males in three adjacent Manhattan neighborhoods with relatively low poverty rates, and where overall diagnosis rates among black males (7.4 per 1,000) and proportions attributable to men who have sex with men (60.0%) were high. HIV-related disparities exist not only between black males and other groups but also within black males. Success addressing the citywide HIV epidemic will be linked to success in the various portions of this highly affected, heterogeneous population.