OBJECTIVES: To determine the association of the frailty phenotype with subsequent healthcare costs and utilization. DESIGN: Prospective cohort study (Study of Osteoporotic Fractures (SOF)). SETTING: Four U.S. sites. PARTICIPANTS: Community-dwelling women (mean age 80.2) participating in SOF Year 10 (Y10) examination linked with their Medicare claims data (N=2,150). MEASUREMENTS: At Y10, frailty phenotype defined using criteria similar to those used in the Cardiovascular Health Study frailty phenotype and categorized as robust, intermediate stage, or frail. Participant multimorbidity burden ascertained using claims data. Functional limitations assessed by asking about difficulty performing instrumental activities of daily living. Total direct healthcare costs and utilization ascertained during 12 months after Y10. RESULTS: Mean total annualized cost+/-standard deviation (2014 dollars) was $3,781+/-6,920 for robust women, $6,632+/-12,452 for intermediate stage women, and $10,755 +/- 16,589 for frail women. After adjustment for age, site, multimorbidity burden, and cognition, frail women had greater mean total (cost ratio (CR)=1.91, 95% confidence interval (CI)=1.59-2.31) and outpatient (CR=1.55, 95% CI=1.36-1.78) costs than robust women and greater odds of hospitalization (odds ratio (OR)=2.05, 95% CI=1.47-2.87) and a skilled nursing facility stay (OR=3.85, 95% CI=1.88-7.88). There were smaller but significant effects of the intermediate stage category on these outcomes. Individual frailty components (shrinking, poor energy, slowness, low physical activity) were also each associated with higher total costs. Functional limitations partially mediated the association between the frailty phenotype and total costs (CR further adjusted for self-reported limitations=1.32, 95% CI=1.07-1.63 for frail vs robust; CR=1.35, 95% CI=1.18-1.55 for intermediate stage vs robust women). CONCLUSION: Intermediate stage and frail older community-dwelling women had higher subsequent total healthcare costs and utilization after accounting for multimorbidity and functional limitations. Frailty phenotype assessment may improve identification of older adults likely to require costly, extensive care.