Objective: This report of one case illustrates the potential effect of chiropractic manipulative therapy on back pain and curve progression in the at-risk, skeletally immature patient with adolescent idiopathic scoliosis. Clinical features: A 15-year-old girl experienced right thoracic scoliosis for 4 years. She received regular rehabilitation and brace treatment for 4 years, but the curvature of the thoracic spine still progressed. The Cobb angle was 46 degrees and surgical intervention was suggested to prevent significant deformity, which may be accompanied by cardiopulmonary compromise. Intervention and outcome: This patient was treated with spinal manipulation two times per week for 6 weeks at the outset, which was gradually decreased in frequency. After 18 months of consecutive treatment, follow-up radiographs and examinations were conducted. The Cobb angle decreased by 16 degrees. Meanwhile, the patient's lower backache eased and there was also an improvement in defecation frequency, which had been problematic. Conclusions: Chiropractic treatment was associated with a reduction in the degree of curvature of adolescent idiopathic scoliosis in this case, after half a year of conventional medical treatment had failed to stop curve progression. This suggests that in at least some severe and progressive cases of scoliosis, chiropractic treatment including spinal manipulation may decrease the need for surgery.