Neurofibromatosis 1 (NF1), a genetic condition most commonly characterized by the presence of dermal neurofibromas and café au lait macules, has a significant impact on Quality of Life (QoL). There is a wide range of phenotypic variability, so that affected individuals may have either medically devastating or relatively mild manifestations that do not impact their daily lives. In this study, the SF-36 and Skindex questionnaires were used to quantitatively investigate the impact of severity and visibility on QoL in an American population. Participants were recruited primarily through advertisements distributed by The Children's Tumor Foundation (CTF). The majority participated by completing a mailed questionnaire in which they rated themselves using Ablon's visibility and Riccardi's severity scales, and then completed the SF-36 and Skindex questionnaires. Participants with NF1 reported a significant impact in all aspects of skin-disease-specific QoL, but the emotional aspect demonstrated the greatest effect. Participants with more visible signs of NF1 reported significantly greater overall effects on their skin-disease-specific QoL than those whose manifestations were more subtle. All domains of general health QoL were affected as well, especially in participants who reported having severe complications. Interestingly, greater visibility was not found to be associated with a significant decrease in general health QoL. These findings are consistent with those found in a French cohort, and demonstrate the utility of incorporating tools designed for use in both the general population and for patients with skin disease in examining the impact of NF1 on QoL. © 2006 Wiley-Liss, Inc.