Aim: To examine cost and mortality differences in postmenopausal women with HR+/HER2- advanced breast cancer. Methods: Using claims data (2007–2013), women with newly diagnosed (de novo) stage IV, or early- or late-recurring metastatic breast cancer were identified. Results: Compared with de novo (n = 121) and late-recurrent (n = 106), early-recurrent (n = 172) patients had significantly higher costs in total and for anticancer systemic agents. Adjusted per patient per month costs for early-recurrent patients were US$13,404, versus US$9955 (de novo) and US$9721 (late-recurrent; p = 0.02). Early-recurrent patients’ risk of death was twice that of de novo patients (p = 0.02). Conclusion: Compared with new diagnosis or late recurrence, early recurrence of HR+/HER2- metastatic breast cancer was associated with higher mortality and healthcare costs.