Although high geographic variation in back surgery rates within the United States have been documented, international comparisons have not been published. The authors compared rates of back surgery in eleven developed countries to determine if back surgery rates are higher: 1) in the United States than in other developed countries, 2) in countries with more neurologic and orthopaedic surgeons per capita, and 3) in countries with higher rates of other surgical procedures. Data on back surgery rates and physician supply were obtained from health agencies within these eleven countries. Country-specific rates of other surgical procedures were available from published sources. The rate of back surgery in the United States was at least 40% higher than in any other country and was more than five times those in England and Scotland. Back surgery rates increased almost linearly with the per capita supply of orthopaedic and neurosurgeons in the country. Countries with high back surgery rates also had high rates of other discretionary procedures such as tonsillectomy and hysterectomy. These findings illustrate the potentially large impact of health system differences on rates of back surgery. Better outcome studies, however, are needed to determine whether Americans are being subjected to excessive surgery or if those in other developed countries are suffering because back surgery is underutilized.