BACKGROUND: Thirty-day readmission penalties implemented with the Hospital Readmission Reduction Program (HRRP) place a larger burden on safety-net hospitals which treat a disproportionate share of racial minorities, leading to concerns that already large racial disparities in readmissions could widen. OBJECTIVE: To examine whether there were changes in Black-White disparities in 30-day readmissions for acute myocardial infarction (AMI), congestive heart failure (CHF), or pneumonia following the passage and implementation of HRRP, and to compare disparities across safety-net and non-safety-net hospitals. DESIGN: Repeated cross-sectional analysis, stratified by safety-net status. SUBJECTS: 1,745,686 Medicare patients over 65 discharged alive from hospitals in 5 US states: NY, FL, NE, WA, and AR. MAIN MEASURES: Odds ratios comparing 30-day readmission rates following an index admission for AMI, CHF, or pneumonia for Black and White patients between 2007 and 2014. KEY RESULTS: Prior to the passage of HRRP in 2010, Black and White readmission rates and disparities in readmissions were decreasing. These reductions were largest at safety-net hospitals. In 2007, Blacks had 13% higher odds of readmission if treated in safety-net hospitals, compared with 5% higher odds in 2010 (P < 0.05). These trends continued following the passage of HRRP. CONCLUSIONS: Prior to HRRP, there were large reductions in Black-White disparities in readmissions at safetynet hospitals. Although HRRP tends to assess higher penalties for safety-net hospitals, improvements in readmissions have not reversed following the implementation of HRRP. In contrast, disparities continue to persist at non-safety-net hospitals which face much lower penalties.