Although skeletal manifestations are a cardinal feature of neurofibromatosis 1, they are largely confined to the axial skeleton and tibiae. In contrast, congenital malformations of the extremities are less common in patients with neurofibromatosis 1, occurring in fewer than 10%. We describe a boy with bilateral, symmetrical polysyndactyly (preaxial polydactyly type IV) and neurofibromatosis 1. This report discusses peripheral skeletal malformations in neurofibromatosis 1 and their possible etiology.