This paper compares the long-term (1970-2002) rates of real growth in health spending per capita in the United States and a group of high-income countries in the Organization for Economic Cooperation and Development (OECD). Real health spending growth is decomposed into population aging, overall economic growth, and excess growth. Although rates of aging and overall economic growth were similar, annual excess growth was much higher in the United States (2.0 percent) versus the OECD countries studied (1.1 percent). That difference, which is of an economically important magnitude, suggests that country-specific institutional factors might contribute to long-term health spending trends.