Background: Over the past 20 years, we have recognized racial/ethnic disparities in breast cancer outcomes, and have attempted to develop outreach, screening, and care strategies to address these. This study explored changes in these disparities over twenty years in presenting stage and overall survival at a single large urban teaching and community hospital with an active cancer outreach program, a member of the NCI Community Cancer Centers Program. Methods: Between 1990 and 2009, 9733 women were diagnosed and treated with breast cancer at our institution. 8918 women with complete race/ethnicity and clinical data were analyzed. The women were grouped into four five-year cohorts, and 3 subgroups-Caucasian, African American, and Latina. All four cohorts were compared for stage migration, while only the initial three cohorts were compared for 5 year overall survival to allow follow-up. Chi-Square tests of proportions were utilized to compare subgroups. Results: Of the 8918 women analyzed, 91.5% are Caucasian, 4.5% African American, and 4% Latina. Over the 20 years of the study, significant stage migration occurred; the total number of women diagnosed with early stage disease(in-situ and localized) increased from 71.7% to 78.7%. Significant stage migration was found for all subgroups of women. Stronger trends were found focusing only on in-situ disease—an overall increase from 14.4% to 30.8%. Five year overall survival of the entire group improved from 78.7% to 85.4%, and also improved for each of the subgroups. Caucasian women were significantly older (60 vs. 54) but the cohort and ethnic findings remained in multivariate analysis. Significant disparities between Caucasians and Latinas for stage and between Caucasians and African American for 5 year survival gradually diminished. Conclusions: Significant improvements are seen in earlier stage presentation and five year overall survival amongst women treated for breast cancer between 1990 and 2009, as well as in subgroups of Caucasian, African American and Latina women. Differences between subgroups diminish and in many cases disappear by the end of the study period, suggesting that strategies may have helped reduce breast cancer disparities.