Scoliosis is a three-dimensional spinal deformity. Although orthotic treatment for moderate adolescent idiopathic scoliosis (AIS) has been well recognized, there are few studies documenting the effectiveness of different casting methods in the fabrication of thoracolumbo-sacral orthoses (TLSO). The current study was a retrospective clinical evaluation of the effectiveness of two commonly used casting methods namely, the frame casting method and the supine with traction casting method in the treatment of AIS. Eighty (80) female patients with AIS were recruited and they were all treated by TLSOs. The frame casting method was used in 37 patients while the remaining 43 patients were under the supine with traction casting method. The responses of spinal deformities under the two different casting methods were analyzed for the period from pre-brace to 2 years after bracing. The studied parameters included the AP Cobb's angle, the apical vertebral rotation and the trunk listing (cervico-sacral lateral offset). The results of the current study showed that the orthoses manufactured from the two casting methods could provide an effective control of AIS (change of Cobb's angle within (+/- 5 degrees). For the frame casting, the Cobb's angles at pre-brace and 2 years after off-brace were 36.0 degrees and 33.8 degrees respectively while for the supine with traction casting, the corresponding Cobb's angles were 32.7 degrees and 34.0 degrees. The frame casting method could give a better control of the apical vertebral rotation at the early stage of treatment (pre-brace = 18.2 degrees and the 4th month = 13.8 degrees while the supine with traction casting method was more effective in the long-term control of the trunk listing (pre-brace = 10mm and 2 years after off-brace = 3.3mm).