Abstract：Background: the presence of osteoporosis in patients with hip and knee osteoarthritis (OA) has important implications for understanding disease progression and providing optimal surgical and medical management. Objective: to determine the prevalence of osteoporosis among patients with osteoarthritis awaiting total knee arthroplasty or total hip arthroplasty aged between 65 and 80 years. Design: cross-sectional observational study. Setting: tertiary referral centre in Newcastle upon Tyne, UK. Subjects: patients with osteoarthritis awaiting total knee hip arthroplasty aged between 65 and 80 years. Methods: lumbar spine, bilateral femoral and forearm bone mineral density (BMD) measurements were obtained using dualenergy X-ray absorptiometry. Results: the cohort consisted of 199 patients with a mean age of 72 years (SD 4), and 113 (57%) were women. The overall rate of osteoporosis at any site was 23% (46/199) and a further 43% (85/199) of patients would have been classified as osteopaenic according to World Health Organization criteria. Osteoporosis was more commonly detected in the forearm (14%) than the lumbar spine (8.5%) and proximal femur of the index side (8.2%). Conclusions: in summary, a significant proportion of patients with end-stage OA have osteoporosis but this diagnosis may be missed unless BMD measurements are performed at sites distant from joints affected by OA.