OBJECTIVE:To describe the patterns of provider use associated with an acute episode of nonspecific low back pain and their impact on cost. METHODS:The analysis is based on a prospective cohort study of patients with acute low back pain followed until they recovered completely or to 6 months. Patients were followed after an initial visit to one of four provider types: private primary care physician, chiropractor, orthopedic surgeon, or HMO primary care physician. Follow-up interviews were conducted at baseline, 2, 4, 8, 12, and 24 weeks; 1,580 (97%) of the participants completed the 6-month follow-up. MAIN RESULTS:Seventy-nine percent of patients saw only the initial provider who began their care for low back pain. Logistic regression revealed that duration of pain prior to initial visit, sciatica, higher Roland disability score, days to functional recovery, interval to complete recovery, referral by initial provider, disk attribution, satisfaction, and the type of index provider were significantly (p < .05) associated with seeking care from multiple provider types. Age, race, gender, and education were not significant. The adjusted proportions of multiple provider type use were 14% (95% confidence interval [CI] 11%, 17%) for the private primary care provider stratum; 19% (95% CI 16%, 23%) for the chiropractic stratum; 30% (95% CI 23%, 37%) for the orthopedic stratum; and 9% (95% CI 5%, 14%) for the HMO primary care physician stratum. Cost of seeing only the index provider was $439 (95% CI $404, $475), and cost of seeing multiple provider types was $1,137 (95% CI $1,064, $1,211) based on the adjusted model. CONCLUSIONS:Use of multiple provider types, is associated with several factors, one of which is the initial provider type. The cost of such use is significant.