Purpose-Disparities in breast cancer stage and mortality by race/ethnicity in the United States are persistent and well known. However, few studies have assessed differences across racial/ethnic subgroups of women broadly defined as Hispanic, Asian, or Pacific Islander, particularly using more recent data.Methods-Using data from 17 population-based cancer registries in the Surveillance, Epidemiology, and End Results (SEER) Program, we evaluated the relationships between race/ ethnicity and breast cancer stage, hormone receptor status, treatment, and mortality. The cohort consisted of 229,594 women 40-79 years of age diagnosed with invasive breast carcinoma between