6503 Background: Factors contributing to racial/ethnic variation in breast cancer treatment delay remain understudied, especially in multi-ethnic population-based samples. Methods: 3,252 women with non-metastatic breast cancer diagnosed between 6/05–2/07 and reported to the Los Angeles County and Detroit, Surveillance Epidemiologic and End Results (SEER) registries were surveyed after initial treatment (mean time from diagnosis = 8.9 months). Latina and African American (AA) women were over- sampled (n=2260, eligible response rate 72.1%). Treatment delay was defined as the patient's report of the duration between when breast cancer was first diagnosed and first surgical procedure (< 1month, 1–3months, ≥4 months) . Multinomial logistic regression models were used to estimate the relative odds of treatment delay by race/ethnicity before and after adjustment for sociodemographics (age, education, income, marital status), clinical factors (number of co-morbidities, health status at diagnosis), and access barriers (difficulty: finding doctors to treat cancer, scheduling surgical procedure, getting to doctor's office). Results: Of the 2195 women who had a surgical procedure, 6.9 % experienced treatment delay of ≥4 months (10.4% Latina, 9.3% AA, 5.5% white women). Latina and AA women were more likely to experience longer treatment delay than white women [OR for ≥4 months/1–3 months vs. < 1 month: 2.18/1.77 for Latinas; 1.78/1.50 for AA (p<.001)] (Table). Racial/ethnic differences persisted after adjustment for sociodemographic, clinical factors, and access barriers [OR for ≥4 months/1–3 months vs. < 1 month: 1.31/1.79 for Latinas; 1.64/1.55 for AA, (p<.001)] (Table), although Latina vs. white differences were no longer statistically significant. Conclusions: Our results confirm that racial/ethnic minorities are vulnerable to delay in receipt of breast cancer treatment in a large population based sample of breast cancer patients. Further work is needed to evaluate the underlying causes of this delay. [Table: see text] No significant financial relationships to disclose.