The availability of dual energy X-ray absorptiometry (DXA) varies markedly in different countries. There is, however, little information to indicate the optimal requirements for this technology. The principal aim of this study was to estimate the requirements for DXA in Europe for the assessment and treatment of osteoporosis. Three assessment scenarios were chosen. The first envisaged screening of all women with DXA at the age of 65 years. A second scenario comprised a screening programme based on the identification of clinical risk factors with the selective addition of BMD tests in those close to an intervention threshold. The third scenario envisaged a case finding strategy where women aged 65 years were identified on the basis of risk factors and referred for DXA. Requirements for women aged more than 65 years were amortised over a 10-year period. A secondary aim was to estimate the number and cost of osteoporotic fractures in Europe. The requirements for DXA in assessment ranged from 4.21 to 11.21 units/million of the population. The most efficient assessment scenario was the use of clinical risk factors with the selective use of BMD. With this scenario, an additional 6.39 units/million would be required to monitor treatment giving a total requirement of 10.6 units/million. In 2000, the number of osteoporotic fractures was estimated at 3.79 million, of which 0.89 million were hip fractures (179,000 hip fractures in men and 711,000 in women). The total direct costs were estimated at €31.7 billion (£21.165 billion), which were expected to increase to €76.7 billion (£51.1 billion) in 2050 based on the expected changes in the demography of Europe.