Objective To investigate the clinical value of serum adiponectin in patients with lung cancer. Methods The serum adiponectin levels in 58 lung cancer patients and 50 healthy controls were detected by radioimmunoassay. Results The serum adiponectin levels in patients with lung cancer were significantly lower than that of in healthy controls（P<0.01). There was no significant difference on serum adiponectin levels between for the lung cancer staging (P>0.05). There was significant difference on serum adiponectin levels between patients with small cell carcinoma and patients with adenocarcinoma and squamous cell carcinoma (P<0.05). There was also significant difference on serum adiponectin levels between lung cancer patients with metastasis and without metastasis (P<0.01). Conclusion The serum adiponectin level might be used as a new marker in the prevention, diagnosis and treatment of patients with lung cancer.