In this study, truncal deformity in patients with scoliosis was evaluated by circumferential scanning using an optoelectronic device (Optronic Torsograph, Anima Corp., Tokyo, Japan). This device generates cross-sectional skin surface topography at 10 axial levels to provide a three-dimensional representation of truncal shape. Ninety-three patients with suspected idiopathic scoliosis were evaluated with conventional Cobb measurements, and their parameters were computed using the device's measurements. The geometric cross-sectional indexes correlated poorly with the Cobb angle and were highly variable during repeated measurements. The optoelectronic device's angle, a measure of centroid curvature, correlated highly with the Cobb angle for primary spinal curves. The highest correlation was observed in thoracolumbar curves. This optoelectronic device has clinical relevance as a method for further scoliosis screening and monitoring the progression of spinal curvature in a patient.