Osteoporotic fractures represent a significant burden to society. The costs of osteoporotic fractures to the UK health care system have not previously been accurately described. In this paper, we quantify the health care and social care costs of fractures occurring in women aged 50 years and over in the UK. We used a variety of data sources. For acute hospital hip fracture costs existing published estimates were used whilst for social care costs a survey of resource use among fracture patients before and after hip fracture was utilized. We undertook a case-control study using the General Practice Research Database to estimate primary care costs. From these data we estimated that the cost of a hip fracture is about 12,000 Pounds, with non-acute hospital costs representing the larger proportion. The other fractures were less expensive, at 468 Pounds, 479 Pounds and 1338 Pounds for wrist, vertebral and other fractures, respectively. For all fractures the annual cost to the UK is 727 million Pounds. Assuming each male hip fracture costs the same as a female fracture, including these would increase the total costs to 942 million Pounds.