Background: Beta-blockers in high target doses are recommended for heart failure with reduced ejection fraction (HFrEF) but not for preserved ejection fraction (HFpEF). Treatment benefits are often more pronounced in high-risk subgroups, and patients with HFpEF with heart rate ≥70 beats per minute have emerged as such a high-risk subgroup. We examined the associations of high-dose beta-blocker use with outcomes in these patients. Methods: Of the 8462 hospitalized patients with heart failure with ejection fraction ≥50% in the Medicare-linked Organized Program to Initiate Lifesaving Treatment in Hospitalized Patients with Heart Failure (OPTIMIZE-HF) registry, 5422 had a discharge heart rate ≥70 beats per minute. Of these, 4537 had no contraindications to beta-blocker use, of which 2797 (2592 with dose data) received prescriptions for beta-blockers. Of the 2592, 730 received high-dose beta-blockers, defined as atenolol ≥100 mg/day, carvedilol ≥50 mg/day, metoprolol tartrate or succinate ≥200 mg/day, or bisoprolol ≥10 mg/day, and 1740 received no beta-blockers. Using propensity scores for the receipt of high-dose beta-blockers, we assembled a matched cohort of 1280 patients, balanced on 58 characteristics. Results: All-cause mortality occurred in 63% and 68% of matched patients receiving high-dose beta-blocker vs no beta-blocker, respectively, during 6 years (median, 2.8) of follow-up (hazard ratio, 0.86; 95% confidence interval, 0.75-0.98; P =.027). The hazard ratios (95% confidence intervals) for all-cause readmission and the combined endpoint of all-cause readmission or all-cause mortality associated with high-dose beta-blocker use were 0.90 (0.81-1.02) and 0.89 (0.80-1.00), respectively. Conclusions: In patients with HFpEF and heart rate ≥70 beats per minute, high-dose beta-blocker use was associated with a significantly lower risk of death. Future randomized controlled trials are needed to examine this association.