In 2012, China's first diagnosis-related group (DRG) payment system was piloted in Beijing. This study explored whether this payment pilot improved quality and reduced costs of acute myocardial infarction (AMI) care in hospitals implementing DRG payment as compared to control hospitals. A difference-in-difference study design was used with regression and considered several quality indicators including aspirin at arrival, aspirin at discharge, β-blocker at arrival, β-blocker at discharge, statin at discharge, in-hospital mortality, and 30-day readmission rates. DRG payment mechanisms without specific mechanisms to promote care quality did not improve quality of AMI care. Future studies should study the impact of cost control mechanisms together with quality improvement efforts to assess how quality of care may be improved within the Chinese healthcare system. These lessons would be helpful to share with lower-middle-income countries undergoing rapid development that are transitioning to a significantly higher burden of non-communicable diseases. • Reforming fee-for-service payment systems to DRG payment may slow quality gains. • Process quality indicators instead of outcome quality indicators are affected by DRG payment. • In addition to changing payment methods, reforms should include building a system supporting quality improvement and incorporate process quality indicators as evaluation metrics. [ABSTRACT FROM AUTHOR]