This study was carried out in order to determine the dependence of selected Hoffmann reflex parameters on type, progression and morphology of idiopathic scoliosis (IS). Data collected from 129 girls with IS (59 progressive and 70 non-progressive cases) aged 7–16 years and 24 healthy subjects were analysed. H-reflex index (IH) and H/M amplitude index (IH/M) were calculated. Progressive left lumbar scoliosis expressed a significant decrease of IH values and a distinct tendency to IH/M depletion compared to non-progressives and controls. Progressive right thoracic scoliosis expressed marked tendency to IH decrease compared to nonprogressive scoliosis. No significant differences in H-reflex parameters were observed between the convex and concave side of the curvature or between types of scoliosis. H-reflex analysis in idiopathic scoliosis supports the hypothesis of a primary neurological disorder in progressive IS.