Baseline demographic and phenotypic characteristics of patients aged ≥50years in the Fabry Outcome Survey (Shire; data extracted June 2014) were compared with younger adults to investigate potential factors influencing treatment decisions in later life. Age groups were defined using age at treatment initiation or at FOS entry for untreated patients: 18-49 (n=1344; 49.5% male; 64.6% received agalsidase alfa enzyme replacement therapy [ERT]); 50-64 (n=537; 35.4% male; 74.3% treated); 65-74 (n=137; 32.1% male; 68.6% treated); and ≥75years (n=26; 26.9% male; 50.0% treated). Successive age groups showed higher median age at first symptom and diagnosis. Median alpha-galactosidase A activity, measured as percentage activity of the midpoint of the normal range, was much greater in females than males of all groups except ≥75years (33.4% in females; 27.8% in males). Patients aged ≥75years showed greater values than patients aged 18-49years for median left ventricular mass indexed to height (62.7 vs 42.4g/m(2.7)), mean ventricular wall thickness (15.0 vs 10.0mm) and prevalence of hypertension (57.7% vs 21.8%), and lower median estimated glomerular filtration rate (Modification of Diet in Renal Disease: 65.6 vs 98.5mL/min/1.73m(2)). Larger proportions in the groups aged ≥50 exhibited cardiac and/or cerebrovascular manifestations compared with patients aged 18-49years. The smaller proportion of patients receiving ERT aged ≥75years compared with the younger groups might reflect relatively milder disease burden or physician/patient reluctance to initiate/continue ERT at this age. Further studies are needed to increase knowledge of Fabry disease and ERT in later life.