PURPOSE: There is limited evidence on the intensity of end-of-life (EOL) care for women < 65 years old, who account for about 40% of breast cancer deaths in the United States. Using established indicators, we estimated the intensity of EOL care among these women. METHODS: We used 2000-2014 claims data from a large US insurer to identify women with metastatic breast cancer who, in the last month of their lives, had more than one hospital admission, emergency department visit, or an intensive care unit (ICU) admission and/or used antineoplastic therapy in the last 14 days of life. Using multivariate logistic regression, we assessed whether intensity of EOL care differed by demographic characteristics, socioeconomic factors, or regions. RESULTS: Adjusted estimates show an increase in EOL ICU admissions between 2000-2003 and 2010-2014 from 14% (95% CI, 10% to 17%) to 23% (95% CI, 20% to 26%) and a small increase in emergency department visits from 10% (95% CI, 7% to 13%) to 12% (95% CI, 9% to 15%), both statistically significant. There was no statistically significant change in the proportions of women experiencing more than one EOL hospitalization (14% in 2010-2014; 95% CI, 11% to 17%) and of those receiving EOL antineoplastic treatment (24% in 2010-2014; 95% CI, 21% to 27%). Living in predominantly mixed, Hispanic, Black, or Asian neighborhoods correlated with more intense care (odds ratio, 1.39; 95% CI, 1.10 to 1.77 for ICU). CONCLUSION: Consistent with findings in the Medicare population, our results suggest an overall increase in the number of ICU admissions at the EOL over time. They also suggest that patients from non-White neighborhoods receive more intense acute care.