Background: Delays in the initiation of breast cancer treatment (e.g., surgery, chemotherapy, adjuvant endocrine therapy) contributes to breast cancer survival disparities. Yet, the use of a cancer dashboard to assess and inform real time assessments of the timing of surgery and systemic treatment by race/ethnicity is unclear. The purpose of this study is to investigate whether a cancer disparities dashboard can be used to assess racial/ethnic differences in the initiation of first line of treatment and timeliness of breast cancer surgery. Methods: A disparities dashboard was built using data from the tumor registry and the electronic medical record’s Data Warehouse. Key fields assessing patient race/ethnicity, cancer stage, receptor status, surgery type, treatments received and dates of surgery. This retrospective analysis included women diagnosed with a new primary breast cancer who underwent definitive surgery at Mount Sinai Hospital (2010-2020). We defined delays as >8 weeks to treatment initiation, and delay to breast surgery as > 6 weeks from diagnosis. Chi-square and t tests were used to assess independent variables (e.g., stage, age) by race/ethnicity. Patient-level multivariable logistic regression was used to evaluate the association between race/ethnicity and delays to initiation of first treatment and surgical delays. Results: Of 8,403 women identified (46.5% non-Hispanic White, 17.7% Black, 16.9% Hispanic), 64.5% had stage I cancer, 80.8% had estrogen receptor cancer. 18.5% of the sample had delays to initial treatment and 42.6% experienced delays to surgery. After adjusting for stage, age and receptor status Black patients compared to non-Hispanic White patients had the greatest likelihood of delayed initial treatment (OR: 3.03; 95% CI:2.6-3.5) or surgery delays (OR:2.45; 95% CI:2.1-2.8). With regards to clinical/sociodemographic factors younger patients (22-39 vs. 40-64; p<0.001), mastectomy surgery type (; p=0.031), higher stage (stage 3 vs.1; p<0.0001), HER2 and TNBC receptor status (vs. ER; p<0.0001),) were more likely to experience surgery delays. Conclusions: Breast cancer treatment delays were more common among minoritized patients compared to White counterparts. A Disparities Dashboard can be used to assess differences in care. These data can be used to inform quality initiatives to improve cancer care delivery for at-risk patient populations who experience worse cancer outcomes.