Objectives. Previous research has generally found that racial/ethnic differences in breast cancer stage at diagnosis attenuate when measures of socioeconomic status are included in the analysis, although most previous research measured socioeconomic status at the contextual level. This study investigated the relation between race/ethnicity, individual socioeconomic status, and breast cancer stage at diagnosis. Methods.Women with stage 0 to III breast cancer were identified from populationbased data from the Surveillance, Epidemiology, and End Results tumor registries in the Detroit and Los Angeles metropolitan areas. These data were combined with data from a mailed survey in a sample of White, Black, and Hispanic women (n=1700). Logistic regression identified factors associated with early-stage diagnosis. Results. Black and Hispanic women were less likely to be diagnosed with earlystage breast cancer than were White women (P<.001). After control for study site, age, and individual socioeconomic factors, the odds of early detection were still significantly less for Hispanic women (odds ratio [OR]=0.45) and Black women (OR=0.72) than for White women. After control for the method of disease detection, the White/Black disparity attenuated to insignificance; the decreased likelihood of early detection among Hispanic women remained significant (OR=0.59). Conclusion. The way in which racial/ethnic minority status and socioeconomic characteristics produce disparities in women’s experiences with breast cancer deserves further research and policy attention.