Background: One of the spine deformities is scoliosis, and Cobb angle is generally used to assess it. Objectives: In this study, a computer-aided measurement system (CAMS) was presented as a new repeatable and reproducible approach to assess the Cobb angle in idiopathic scoliosis patients. Methods: Python libraries, including OpenCV and NumPy were used for image processing and design of the software. To assess the repeatability and reproducibility of the CAMS, a series of 98 anterior-posterior radiographs from patients with idiopathic scoliosis were used. Assessments were done by five independent observers. Each radiograph was assessed by each observer three times with a minimum break of two weeks among assessment. The single measure intraclass correlation coefficient (ICC), the mean absolute difference (MAD), and the standard error measurement (SEM) values were used for intra-and inter-observer reliability. Results: The inter-observer analysis indicated that the ICCs ranged from 0. 94-0. 99, and the MAD between manual and CAMS were less than 3°, . For intra-observer measurements, the combined SEM between all observers for the manual and CAMS was 1. 79°,and 1. 27°, , respectively. An ICC value of 0. 97 with 95% confi, dence interval (CI) was excellent in CAMS for inter-observer reliability. The MAD of CAMS was 2. 18 ,2. 01 degrees. Conclusions: The CAMS is an effective and reliable approach for assessing scoliotic curvature in the standing radiographs of thoraco-lumbar. Moreover, CAMS can accelerate clinical visits, and its calculation results are reliable.