Background: Chronic low-back pain is a significant public health problem for which few therapies are supported by predictable outcomes. In this report, practice activities and 1-month outcomes data are presented for 93 chiropractic patients and 45 medical patients with chronic, recurrent low-back pain.Design: A prospective, observational, community-based feasibility study involving chiropractors and family medicine physicians.Setting: Forty private chiropractic clinics, the outpatient clinic of the Department of Family Medicine at Oregon Health Sciences University, and 5 other Portland area family medicine clinics.Outcomes measures: The main outcome measures were pain severity, functional disability, sensory and affective pain quality at 1 month, and patient satisfaction assessed at 7 to 10 days and at 1 month.Results: Although differences were noted in age, sex, education, and employment, the patients were closely matched at baseline with respect to frequency, severity, and type of low-back pain and the psychosocial dimensions of general health. The treatment of choice for chiropractors was spinal manipulation and physical therapy modalities; for medical physicians antiinflammatory agents were most frequently used. Chiropractic patients averaged 4 visits, and medical patients averaged 1 visit. On average, chiropractic patients showed improvement across all outcomes: 31% change in pain severity, 29% in functional disability, 36% in sensory pain quality, and 57% in affective pain quality. Medical patients showed minimal improvement in pain severity (6%) and functional disability (1%) and showed deterioration in the sensory (29%) and affective (26%) dimensions of pain quality. Satisfaction scores were higher for chiropractic patients. Outcomes for medical patients were heavily dependent on psychosocial status at baseline.Conclusion: Patients with chronic low-back pain treated by chiropractors show greater improvement and satisfaction at 1 month than patients treated by family physicians. Nonclinical factors may play an important role in patient progress. Findings from the Health Resources and Services Administration-funded project will include a report on the influence of practice activities, including more frequent visits by chiropractic patients, on the clinical course of low-back pain and patient outcomes. (J Manipulative Physiol Ther 2000;23:239-45).