OBJECTIVES: This study quantified AIDS incidence in Massachusetts in relation to economic deprivation. METHODS: Using 1990 census block-group data, 1990 census population counts, and AIDS surveillance registry data for the years 1988 through 1994, we generated yearly and cumulative AIDS incidence data for the state of Massachusetts stratified by sex and by neighborhood measures of economic position for the total, Black, Hispanic, and White populations. RESULTS: Incidence of AIDS increased with economic deprivation, with the magnitude of these trends varying by both race/ethnicity and sex. The cumulative incidence of AIDS in the total population was nearly 7 times higher among persons in block-groups where 40% or more of the population was below the poverty line (362 per 100,000) than among persons in block-groups where less than 2% of the population was below poverty (53 per 100,000). CONCLUSIONS: Observing patterns of disease burden in relation to neighborhood levels of economic well-being elucidates further the role of poverty as a population-level determinant of disease burden. Public health agencies and researchers can use readily available census data to describe neighborhood-level socioeconomic conditions. Such knowledge expands options for disease prevention and increases the visibility of economic inequality as an underlying cause of AIDS.