To distinguish the clinical features of amputation due to congenital constriction band syndrome from those of transverse deficiency, 42 cases of constriction band syndrome and 27 cases of transverse deficiency were analysed. All the transverse deficiencies were unilateral. Two cases of transverse deficiency were associated with pectoral muscle absence, whereas amputation from constriction band syndrome was often associated with similar anomalies in other parts of the body. The level of amputation of transverse deficiency was more proximal than that of constriction band syndrome. Rudimentary fingers and/or nails were common in transverse deficiency but there were few in constriction band syndrome. Various degrees of bone hypoplasia existed in adjacent fingers or in a proximal part of the affected limb in transverse deficiency, but there were no such findings in constriction band syndrome.