England, France, Germany, the Netherlands, and Sweden spend less as a share of gross domestic product on hospital care than the United States while delivering high-quality services. All five European countries have hospital payment systems based on diagnosis-related groups (DRGs) that classify patients of similar clinical characteristics and comparable costs. Inspired by Medicare's inpatient prospective payment system, which originated the use of DRGs, European DRG systems have implemented different design options and are generally more detailed than Medicare's system, to better distinguish among patients with less and more complex conditions. Incentives to treat more cases are often counterbalanced by volume ceilings in European DRG systems. European payments are usually broader in scope than those in the United States, including physician salaries and readmissions. These European systems, discussed in more detail in the article, suggest potential innovations for reforming DRG-based hospital payment in the United States.