To evaluate the impact of disease visibility on psychological stress factors in neurofibromatosis type 1 (NF1) and to explore the body image of NF1 patients. 228 adult NF1 patients participated in this cross-sectional survey. The questionnaire assessed perceived disease visibility and patients’ body image. Outcome parameters were depression, distress and quality of life. Mediation models were performed to test if body experience mediated the effect of disease visibility on outcome parameters. Adult NF1 patients had a negative body image, expressed by bodily insecurity/uneasiness and fewer feelings of attractiveness and self-confidence. Compared to the body image of patients with other disfiguring diseases, patients with NF1 felt less attractive, displayed less self-confidence (women: p< 0.001; men: p< 0.001) and were more insecure/uneasy and sexually dissatisfied with their bodies (men: p< 0.001; women: p≤ 0.12, d= 0.28). The found effect of disease visibility on psychological stress was completely mediated by how patients experienced their bodies. Our study shed light on the importance of how NF1 patients experience and appraise their own bodies. We revealed that body image is an important link between disease visibility and psychological well-being. The body image of patients can be improved with psychotherapeutic interventions.