Patients who suffer from Down Syndrome may have a number of orthopedic and rheumatologic disorders. Recent life-table study of live-born individuals with Down Syndrome reports a survival rate of >50% to the age of 50. Therefore some osteoporotic-related disorders have to be considered. Femoral neck fracture is a typical disease when these patients are elderly, often due to traumatic episodes or to violent seizures. We report the case of a 50-year-old Down Syndrome patient who had progressive loss of mobility and standing capacity associated with mental confusion, first considered to be a neurological disturbance. He lived with his family and led a standard lifestyle for his condition with a normal ability to walk. The parents reported he had not fallen and that, before the episode, he had been able to walk and stand normally. After examination by a multidisciplinary team of physicians, the diagnosis was a bilateral femoral neck fracture. The patient was then treated with a one-stage bilateral hip hemiarthroplasty. The pathogenesis of osteoporosis Down Syndrome patients is multifactorial and includes a sedentary lifestyle and poor mobility, endocrine abnormalities, and anticonvulsant medications. The musculoskeletal disorders, however, are not the only medical problems these patients have to face. Because of the limited communicative skills, clinical symptoms and signs of early disease frequently go undetected or are misdiagnosed for long periods of time. For this reason we recommend annual systematic screening for health problems including screening for osteoporosis.