A two and a half-year prospective study was carried out to determine incidence rates and distributions of various parameters associated with idiopathic scoliosis. Data were also collected on the progression curves detected at the initial screening. The results showed: (1) that the incidence rate was 13.6 per cent with a female-to-male ratio of 1.2:1, (2) that the most common type of curve was thoracolumbar, and (3) that spontaneous improvement occurred in approximately 22 per cent of those patients followed for an average of one year.