The roles of many genes in the pathophysiology of lung cancer have been investigated in different studies. Cyclin D1 (CCND1) gene plays a significant role in the transition from G1 to S phase of the cell cycle and in the phosphorylation of retinoblastoma tumor suppressor protein. In this study, we aimed to identify the relationship between CCND1 A870G gene polymorphism with lung cancer. CCND1 A870G genotypes were determined in 75 patients with lung cancer and in 65 control subjects. DNA was isolated from blood samples and then CCND1 A870G gene polymorphism was identified using PCR and RFLP assay. The distribution of CCND1 A870G polymorphism did not show any significant differences in all lung cancer patients and controls. There was no correlation between CCND1 A870G polymorphism and histopathological findings. However, the AA + AG genotype was significantly higher in metastatic patients, when compared with non-metastatic patients. Thus, the results show that CCND1 gene polymorphism may be a predictor for detecting patients with poor survival who having metastatic disease.