Introduction: Bone metastases may change the primary treatment modality, especially if the bone is the only site of metastasis in patients considered to be in the early stage of lung cancer. It is usually diagnosed by imaging techniques. However, the diagnostic yields of imaging methods are limited. Some bone markers such as propeptides of type-1 collagen, pyridinoline cross-links and deoxypyridinoline (D-PYD) cross-links, serum osteocalcin, alkaline phosphatase are thought to be useful in the detection of bone metastasis in lung cancer. Thus, we aimed to determine the clinical usefulness of bone turnover markers in the assessment of bone metastases in patients with lung cancer.