Abstract: The biomarkers of bone metabolism are proteins, which are synthesized by the osteoblast and osteoclast and are released into the bloodstream or circulation as fragments during the formation or degradation of type I collagen. Because some of these fragments are small, they are filtered by the kidney into urine, but the larger fragments which are not filtered are detected in the blood samples. Disorders or disease conditions of skeletal metabolism result in the release of these fragments, which are products of osteoblastic and/or osteoclastic activity. Measurements of these biomarkers of bone metabolism by immunoassay methods show promise as important adjuncts in the early diagnosis of bone changes. These biomarkers are also important in the evaluation and management of skeletal complications of sickle cell disease and other disorders of bone; however they are affected by a variety of physiological and pathological factors. In conclusion, biochemical bone biomarkers are convenient, non-invasive indices of bone metabolic activities, but other analytes such as parathyroid hormone and 25-hydroxycholecalciferol or calcidiol may also be considered.