The inverse relationship between generalized osteoarthritis (GOA) and primary osteoporosis (OP) was noted clinically by distinguished physicians four decades ago. The most impressive clinical observations are the general absence of OA in the head of the femur excised during the treatment of fracture, and the rarity of atraumatic hip and spine fractures in OA cases. Patients with primary OP and those with OA, although both common in elderly people, appear to represent anthropometrically different populations. The typical GOA patients tend to be mesomorph, whereas the typical OP type I and type II patients tend to be ectomorph. Although there is an inverse relationship between generalized OA and primary OP, in clinical practice a combination of OP and OA is coincidentally encountered, in particular in the very elderly. However, if osteoarthritic subjects develop osteoporotic fracture, they do so at a later age, suggesting that OA or a related factor might have a protective effect on the progression of OP.