Objective:To examine the relationship between income and AIDS rates in Los Angeles County (LAC) by race/ethnicity.Methods:1990 US census data were used to classify LAC postal zones (zip codes) by median household income into low‐, middle‐, and high‐income strata. AIDS rates were calculated for each income stratum based on 15805 AIDS cases diagnosed from 1987 through 1992 and reported to the county health department.Results:The AIDS rate was highest among residents of low‐income areas (252.8 per 100 000), intermediate among residents of middle‐income areas (161.2 per 100 000), and lowest among residents of high‐income areas (82.0 per 100 000). This trend in rates was present in all racial/ethnic groups examined and was most pronounced among whites (675.1, 226.7, and 88.4 per 100 000, respectively). Residents of low‐income areas accounted for 78% of AIDS cases among blacks, 67% among Hispanics, and 47% among whites.Conclusions:These findings suggest a strong inverse relationship between income and AIDS rates in LAC that is consistent across racial/ethnic groups. Prevention programs and treatment services should be directed most intensively to low‐income neighborhoods in this county.