BACKGROUND: The accessibility and outcomes of cyclin-dependent kinase 4 and 6 inhibitors (CDKi) in metastatic breast cancer (MBC) according to demographic factors are unknown. RESEARCH DESIGN AND METHODS: Retrospective review of patients with ER+ MBC prescribed first-line CDKi therapy from January 2015 through December 2022. Abstraction included time from CDKi prescription to drug initiation (TTI), time from CDKi initiation to progression (TTP), time from CDKi initiation to death or 6/30/2022, and variables (age, race, partner status, insurance type, BMI, number of comorbidities). Descriptive, comparative, and correlational statistics are used. CONCLUSIONS: Medicaid insurance is associated with worse outcomes of MBC therapy, not attributed to TTI delay. Personalization of support may be helpful.