BACKGROUND:Among traditional Medicare patients, discharge to home health agencies (HHAs) has become the most common postacute care (PAC) setting following hospitalization. OBJECTIVES:Estimate the effects of receiving care from home health agencies (HHAs) that specialize in providing PAC. RESEARCH DESIGN:Cross-sectional study using an instrumental variables approach with a differential distance between patients and specialized HHAs. SUBJECTS:Using 100% Medicare fee-for-service claims, we identified 853,780 traditional Medicare patients receiving postacute home health care in 2019. Postacute episodes were defined as home health starting within 14 days of hospital discharge. The sample averaged 56% female, 20% dual-eligible, and 84% White. Patient demographic and clinical characteristics were mostly similar between those who received care at PAC-specialized and nonspecialized HHAs. MEASURES:HHAs were categorized as PAC-specialized if they were in the 75th percentile nationally for share of postacute episodes. Main outcomes included hospitalization, skilled nursing facility (SNF) use, and mortality during the home health spell and within 6 weeks of HHA discharge. RESULTS:The instrument was strong (F-statistic=905.2), with each mile of differential distance reducing specialized HHA probability by 0.8 percentage points (pp). During home health spells, patients at specialized HHAs experienced significantly lower hospitalization risk (-2.1 pp) and SNF admissions (-0.3 pp). Postdischarge, we observed differences in hospitalizations (-0.8 pp during the discharge week and 0.9 pp at 6 wk post-HHA discharge). Mortality rates were consistently lower during the discharge week (-1.3 pp) and within 6 weeks postdischarge (-1.1 pp). CONCLUSIONS:Specialized HHAs appear to achieve better outcomes during treatment and have lower mortality rates both during and after care, suggesting important implications for postacute care delivery optimization.