Objectives: To determine the diagnostic validity of the width of the inferior mandibular cortex on dental panoramic radiographs (DPRs), as measured by an Active Shape Model (ASM) method in combination with a clinical risk index, for the diagnosis of osteoporosis in peri- and post-menopausal women. Methods: Volunteer female subjects in the 45 to 70 year age band, recruited from four European centres, underwent dual x-ray energy absorptiometry (DXA) of the hip and lumbar spine, to provide a gold standard diagnosis of osteoporosis, and a DPR examination. A questionnaire was completed for each subject to identify factors related to osteoporosis risk and calculate a clinical risk index (OSIRIS). A manually initialised ASM method was used to derive cortical width measurements from each radiograph. ROC analysis was used to identify the most effective clinical index. Logistic regression analysis was used to build a model, with the presence or absence of osteoporosis as the dichotomous dependent variable and OSIRIS and the radiographic data as independent variables. Results: ROC analysis gave an Az value for OSIRIS of 0.841 (95% CI: 0.811 to 0.868). The sensitivity and specificity of the combined radiographic-clinical risk assessment were 38.6% and 97.9% respectively. Conclusions: Combining the cortical width measurement and the clinical risk index provided a high specificity method for detection of subjects with osteoporosis, although sensitivity was modest. This model would be most suitable for use in the context of restricted availability of DXA. This work was supported by a research and technological development project grant from the European Commission FP5 'Quality of Life and Management of Living Resources' (QLK6-2002-02243).