The purpose of this study was to identify the above mentioned therapy on the reduction of functional leg length inequality, by the manipulation(Thonpson technique). In 8 patients who have been chronically ill with low back pain and functional leg length inequality, for past 12 weeks, we analyzed and observed the progress of symptom and sign on pelvis(femur head line level, ilium length, ilium rotation), using by X-ray. The results after 12 week treatment, compared with before treatment, were as follows : 1. The improved in femur head line in the manipulation after 12 week treatment was very significant(p<.01) 2. The improved in ilium length in the manipulation after 12 week treatment was very significant(p<.01) 3. The improved in ilium rotation in the manipulation after 12 week treatment was significant(p<.05).