STUDY DESIGN: Serial, cross-sectional, nationally representative surveys of noninstitutionalized US adults. OBJECTIVE: To examine expenditures on common ambulatory health services for the management of back and neck conditions. SUMMARY OF BACKGROUND DATA: Although it is well recognized that national costs associated with back and neck conditions have grown considerably in recent years, little is known about the costs of care for specific ambulatory health services that are used to manage this population. METHODS: We used the Medical Expenditure Panel Survey to examine adult (aged 18 yr or older) respondents from 1999 to 2008 who sought ambulatory health services for the management of back and neck conditions. We used complex survey design methods to make national estimates of mean inflation-adjusted annual expenditures on medical care, chiropractic care, and physical therapy per user for back and neck conditions. RESULTS: Approximately 6% of US adults reported an ambulatory visit for a primary diagnosis of a back or neck condition (13.6 million in 2008). Between 1999 and 2008, the mean inflation-adjusted annual expenditures on medical care for these patients increased by 95% (from $487 to $950); most of the increase was accounted for by increased costs for medical specialists, as opposed to primary care physicians. During the study period, the mean inflation-adjusted annual expenditures on chiropractic care were relatively stable; although physical therapy was the most costly service overall, in recent years those costs have contracted. CONCLUSION: Although this study did not explore the relative effectiveness of different ambulatory services, recent increasing costs associated with providing medical care for back and neck conditions (particularly subspecialty care) are contributing to the growing economic burden of managing these conditions.