In primary care and physical therapy settings, we evaluated an intervention for chronic back pain patients which incorporated fear reducing and activating techniques. Primary care patients seen for back pain in primary care were screened to identify persons with significant activity limitations 8-10 weeks after their visit. Eligible and willing patients were randomized (N=240). A brief, individualized program to reduce fear and increase activity levels was delivered by a psychologist and physical therapists. Over a 2 year follow-up period, intervention patients reported greater reductions in pain-related fear (P<0.01), average pain (P<0.01) and activity limitations due to back pain (P<0.01) relative to control patients. The percent with greater than a one-third reduction in Roland Disability Questionnaire scores at 6 months was 42% among Intervention patients and 24% among control patients (P<0.01). Over the 2 year follow-up, fewer intervention patients reported 30 or more days unable to carry out usual activities in the prior 3 months (P<0.01). The adjusted mean difference in activity limitation days was 4.5 days at 6 months, 2.8 days at 12 months, and 6.9 days at 24 months. No differences were observed in the percent unemployed or the percent receiving worker's compensation or disability benefits, but these outcomes were relatively uncommon. We conclude that an intervention integrating fear reducing and activating interventions into care for chronic back pain patients produced sustained reductions in patient fears, common activity limitations related to back pain, and days missed from usual activities due to back pain.