Objective: To evaluate the efficacy of acupuncture in treating chronic non-specific low back pain. Methods: Ten patients with chronic low back pain were selected to receive 9 acupuncture treatments over a three-week period with point selection based on syndrome differentiation in Chinese medicine. The BROM Instrument for assessment of back range of motion; subjective evaluation with Visual Analog Scale of Pain (VASP) ratings, Oswestry Disability ratings, objective measurements including Algometry, and Flexion and Extension ratings to investigate the range of motion were used for comparing the large, medium and small effect sizes of baseline, treatment and follow-up phases. Results: Clinical significance of pain relief was shown in all parameters assessed. A large effect size was detected in VASP, Oswestry and Algometry. A small effect size was demonstrated in Flexion/Extension. Needling over short period time (3 weeks) could relieve the pain, but the muscular-skeletal function measured by BROM persists. To treat patients exclusively by needling for statistical purposes can not be justified, because by merely relieving pain, permanent improvement in function may not be achieved. Conclusion: Acupuncture offers an effective alternative for the clinical management of chronic low back pain, significant improvement in most of the parameters evaluated, but the functional improvement was not as satisfactory as pain relieving. Further study with larger sample size focuses on long-term efficacy and functional improvement for chronic low back pain is recommended.