Twelve patients aged ten to eighteen years suffering from idiopathic scoliosis and a minor spondylolisthesis were treated by Milwaukee- or Bostonbrace during 12 to 38 months. According to Wiltse's results the spondylolysis was expected to heal under brace treatment in a certain number of cases. In fact it only happened twice out of twelve cases. The least chance for success was found when the tips of the interarticular bone parts showed a sclerosis in the x-ray-picture. We may suggest that brace treatment of minor spondylolysis or spondylolisthesis in adolescence is obviously not useful. Long term results are even worse.