The occurrence of bone decalcification during rheumatoid arthritis is well documented, despite discrepancies among published data. The most recent studies support a decrease in bone mass, especially at the proximal femur, although estimations of the extent of bone loss ascribable to rheumatoid arthritis vary. The fracture risk is increased by approximately 100% in rheumatoid arthritis patients. Bone mass is negatively correlated with functional impairment, joint motion restriction and disease activity as assessed by laboratory tests for inflammation. Increased physical activity can reduce bone loss. Markers for bone formation (osteocalcin, procollagen type I carboxy-terminal propeptide) are normal or decreased, whereas markers for bone resorption (hydroxyproline, pyridinoline, and deoxypyridinoline) are elevated. This decoupling of bone formation and resorption may be responsible for bone loss. Although estrogen therapy can keep in check menopause-related bone loss, earlier findings suggesting that estrogens may have beneficial effects on the joint disease itself have been disproven. The value of preventive bisphosphonate therapy is currently under debate.