Analysis of AIDS mortality data for New York City for 1981–1987 reveals that Puerto Ricans represent the racial/ethnic group most severely affected by this city's AIDS epidemic. Cumulative age-adjusted AIDS mortality rates among Puerto Rico-born males are significantly higher (362 per 100,000) than among blacks (267), whites (182), or other Hispanic (217) males, and cumulative age-specific mortality rates for males are highest for the Puerto Rico-born in every adult age group. AIDS proportional mortality analysis indicates that in 1987 the proportion of all deaths due to AIDS was 10% among those Puerto Rican-born, 12% among other Hispanics (which includes at least 50% United States-born Puerto Ricans), 6% among blacks, and 2% among whites.