We reviewed 90 consecutive patients with various neuromuscular diseases and a progressive spine deformity treated with a prefabricated Boston-type underarm corrective brace. Of these, 38 patients had spastic tetraplegia; seven, syndrome-related muscular hypertonia; 24, muscular hypotonia; and 21, myelomeningocele. The mean age at the treatment start was 9.2 years (range, 1.4-17.7 years). Twenty-four were ambulating and 66 wheelchair-bound. Hypotonia was the dominant type of muscle involvement in 49, spasticity in 28, and athetosis in 13 patients. The mean pretreatment Cobb angle was 47 degrees, with a range from 23 to 95 degrees. The mean brace-induced Cobb-angle correction was 60%, thus well comparable to that in idiopathic scoliosis. However, this did not predict favorable treatment results. At the follow-up, on average 3.1 years (range, 1-5.5 years) after weaning from the brace, the brace treatment was successful in 23 patients. Successful was defined as <10 degrees curve progression during the observation time and a good brace compliance. Forty-one patients discontinued the brace treatment, and 19 progressed despite adequate brace wear. Five patients are still in treatment, and two have died. Successful treatment was seen in ambulating patients with muscle hypotonia and short thoracolumbar/lumbar curves measuring <40 degrees as well as in nonambulating patients with spastic short lumbar curves. These types of neuromuscular scoliosis may be the only ones to respond to brace treatment. In other cases, the brace treatment cannot be expected to have a lasting corrective effect although it can be used as sitting support.