A global, patient-reported registry has been established to characterize the course of disease and track clinical outcomes in patients with fibrodysplasia ossificans progressiva (FOP), an ultra-rare genetic condition of progressive heterotopic ossification (HO) that results in ankylosis of joints and renders most affected individuals immobile by the second decade of life. Here, we present baseline phenotypes on 299 patients (median age 21 years;​ range 0.1 to 78 years) from 54 countries based on aggregate data from the International FOP Association (IFOPA) Global Registry (the “FOP Registry”). The mean current age of the patients is 23.7 years (range, 0.1 to 78 years). Baseline characteristics are presented for FOP diagnosis, HO, flare-ups and precedent events, system-based prevalent symptomatology, encounters with medical and dental care providers, Patient Reported Outcomes Measurement Information System (PROMIS) Global Health Scale scores, physical function, as well as the use of aids, assistive devices, and adaptations. Correlations of PROMIS Global Health scores with HO burden and physical function are calculated. Associations of joint mobility with PROMIS Global Health scores, physical function, and use of aids, assistive devices, and adaptations are summarized. Overall, the FOP Registry database contains a broad sample of the global FOP patient population, providing a useful tool for expanding knowledge of FOP, designing clinical trials and facilitating evidence-based decisions about the optimal monitoring and management of affected individuals.