We aimed at studying fracture risk in patients with Duchenne's muscular dystrophy (DMD), Becker's muscular dystrophy (BEMD), and spinal muscular atrophy type II and III (SMA II and III). A self-administered questionnaire was mailed to 293 patients with DMD, BEMD, SMA II or SMA III of which 229 returned the questionnaire. Each respondent was compared with an age- and gender-matched control subject. The mean age was 23.9 +/- 15.9 years for the patients and 23.3 +/- 16.5 years for the controls. There were significantly more fractures among patients than controls after the diagnosis was made (RR = 1.9), but not before. The patients had more fractures of the femurs, lower legs, and upper arms than the controls. Low energy fractures were more frequent in patients than controls (9% vs 0%). Many fractures in the femurs (40%), lower legs (35%), and feet and toes (44%) led to a permanent loss of function. Loss of ambulation was the major risk factor for fractures. In conclusion, fracture risk is increased in neuromuscular disease.