Abstract Background: The relationship between osteoarthritis and osteoporosis has exhibited contradictory features over the past four decades. Numerous observational and longitudinal studies have shown an inverse association between the two diseases and a protective effect of one against the other. On the other hand, some studies show that patients with OA have impaired bone strength and are more prone to fractures. Aim of Study: The study's main objective was to determine the correlation between the bone mineral density (BMD) of the spine and hip (femoral neck) of postmenopausal women with radiologically determined OA of the knee. Patients and Methods: This case-control study included 50 female patients with knee OA diagnosed clinically accord-ing to the American College of Rheumatology (ACR) criteria and who had radiographic evidence of grade II,III and IV knee OA as judged by the Kellgren and Lawrence scale (KL) and 50 matched healthy individuals. We evaluated a total of 100 participants aged ≥50 years who underwent knee radiography and dual-energy X-ray absorptiometry. Spearman correlation coefficient was used to test the association of severity of OA knee with BMD. Results: Compared to the control group, we found statisti-cally significantly lower T-scores of the spine p=0.01, as well as of the hip T-score p<0.0001. The values of T-score of the spine and hip are lower in more severe forms of OA (X-ray stage III and IV, according to KL grade), p=0.009 and p<0.001 respec-tively. Correlation analyses revealed that KL grades and age were significantly and negatively correlated with hip T-score p<0.0001 not with the spine T-score. Conclusion: Postmenopausal women with radiographic knee OA had significantly lower T-scores of the hip and spine as compared to the control group without OA. Hip T-scores de-crease with severity of OA knee. These data support the fact that the two conditions may be related to each other and pri-mary care physicians must look for these two conditions in co-existence. Primary prevention of either of the two conditions should be advised, if the other condition coexists in the same patient.