CONTEXT: Pain is a major symptom in adults with fibrous dysplasia/McCune-Albright syndrome (FD/MAS) and response to current treatments, including bisphosphonates and standard analgesics (nonsteroidal anti-inflammatory drugs and opiates) is unpredictable. No studies have explored whether the type of pain is variable in this patient group. OBJECTIVE: To determine the frequency of neuropathic-like pain in patients with FD/MAS. DESIGN: Retrospective, dual registry study. SETTING: Community. PATIENTS: FD/MAS online registries: the US-based Familial Dysautonomia Foundation (FDF) and the UK-based Rare and Undiagnosed Diseases (RUDY) study. INTERVENTION: Subjects completed questionnaires to evaluate the presence of features of neuropathic-like pain (painDETECT) and the impact on sleep quality (Pittsburgh Sleep Quality Index) and mental health (Hospital Anxiety and Depression Scale). Descriptive statistics were used to characterize the prevalence and associated burden of neuropathic-like pain. MAIN OUTCOME MEASURES: Incidence of neuropathic, nociceptive, and unclear pain. RESULTS: Of 249 participants, one third experienced neuropathic-like pain. This group had statistically significantly (P < 0.001) worse mental well-being and sleep in comparison to those with predominately nociceptive pain. CONCLUSIONS: Neuropathic-like pain is common in patients with FD/MAS and associated with worse quality of life. Evaluation of pain in patients with FD/MAS should include assessment of neuropathic-like pain to guide personalized approaches to treatment and inform future research.