Various inflammatory diseases such as rheumatoid arthritis, ankylosing spondylitis and systemic lupus erythematosus are associated with musculoskeletal complications including osteoporosis. They are related to osteoporosis and increased risk of fractures independent of other risk factors like low physical activity, nutritional deficiency, hypovitaminosis D and inadequate calcium intake, as well as glucocorticoid treatment. The pathogenesis of osteoporosis in inflammatory diseases is multifactorial. The concept of osteoimmunology is based on growing insights into the relationship between the immune system and bone. The association between inflammation and osteoporosis can be explained by the link between osteoclast, macrophage colony stimulating factor and proinflammatory cytokines. Here we discuss the etiopathogenesis underlying the inflammatory loss of bone in rheumatoid arthritis, ankylosing spondylitis and systemic lupus erythematosus. Turk J Phys Med Rehab 2012;58:319-25.