Using cancer registry data, we focus on racial and ethnic disparities in stage of breast cancer diagnosis in Cook County, IL. The county health system is the "last resort" health-care provider for low-income persons. Socioeconomic status is measured using empirical Bayes estimates of tract-level poverty, specific to non-Hispanic whites, non-Hispanic blacks or Hispanics in one of three age groups. We use ordinal logistic regression with non-proportional odds to model stage. Blacks and Hispanics are at greater risk for regional and distant stage diagnosis, but the disparity declines with age. Women in high-poverty areas are at substantially greater risk for late-stage diagnosis. The effects of poverty do not differ by age or across racial and ethnic groups.