Thirty patients with acute, painful vertebral compression fracture were studied. Certain vertebrae, namely T8, T12, L1 and L4, were more likely to fracture. The majority occurred spontaneously (46%) or after trivial strain (36%). Of the former, 30% occurred whilst in bed. Radiation to the flanks and anteriorly was common (66%) but leg radiation was uncommon (6%). Associated symptoms noted were: nausea (26%), abdominal pain (20%), chest pain (13%). Straining exacerbated pain in only 60%. The position of comfort was lying flat (43%) or sitting (36%) but 16% found standing or walking most comfortable. The correct diagnosis was made at the first visit in only 43% of patients. In the remainder there was a mean delay of 4.5 days before diagnosis. This poor diagnostic rate may be improved if other clinical features of osteoporosis such as kyphosis and a previous history of wrist and hip fractures are recorded, particularly when acute back pain occurs in bed. Full thoracic and lumbar X-rays may be required because pain and site of pathology may not coincide. Bone scanning may be necessary if immediate X-rays are normal. In early management the position of most comfort may be preferable to complete bed rest.