Scoliosis has been reported in 40 to 60 percent of patients with Marfsn's syndrome. The tensile strength of tissues in which the collagen is a major component has been to be reduced in this disease. An abnormality of cross-linking in the α2(I) peptide chain of collagen is the simplest explanation for this observation. We experienced a case of scolisis with Marfan's syndrome in whom Cotrel-Dubousset instrumentation was csrried out successfully and bilateral pneumothorax was observed in 10 days postoperatively. The occurrence of this complication, which has not been previously reported in the literature, suggests that excessive distractional and rotational force during procedure may be harzsrdous in the patient with intrinsic collagen weakness.