The notion that vascular alterations represent a major feature of the pathogenesis of neurofibromatosis (NF) has been supported by an increasing number of observations. We present data about skin Morgan angiomas in the general US white population and a cohort of patients with NF-1 and their unaffected relatives. Among patients with NF-1, angiomas were significantly more common, but not so among unaffected relatives. The striking nature of skin angiomas in some patients is illustrated by a mother-daughter pair with innumerable lesions of early onset. The mother also had a large venous angioma and a constriction of the siphon of an internal carotid artery.