Osteoporosis is a known consequence of stroke, associated with an increased incidence of fractures, mainly of the hip, leading to further disability. The pattern of bone loss seen in stroke patients is different from that usually encountered with postmenopausal osteoporosis, since it is limited to the paretic side and more evident in the upper extremities. Several factors appear to have an influence on bone mass in stroke patients, such as the degree of paresis, gait disability and the duration of immobilization. The pathogenesis of osteoporosis after stroke remains unclear. Paresis, reduced mobility and reduced bone load seem to play a major role. Other factors such as nutritional and iatrogenic ones may also play an important part. In this paper, the clinical evidence, pathophysiology and possible treatments of post-stroke osteoporosis will be reviewed.