Aim: Lung cancer (LC) is a fatal disease characterized by uncontrolled proliferation of airway epithelial cells and caused by genetic or environmental factors. LC is one of the most common types of cancer and the leading cause of cancer-induced deaths. The most important factors in the etiology of LC are smoking and exposure to tobacco smoke. Micro RNAs (miRNAs) are short and non-coding RNAs that contain hairpin structure and approximately 1824 nucleotides. Like the other genes, miRNAs are transcribed from DNA and involved in gene regulation without converting to protein. Previous studies have determined that miRNA expression levels are associated with the development and progression of malignant tumors and that miRNAs can act as oncogene or tumor suppressors. The aim of our study was to determine any association between expression levels of miR200b and miR1274a and lung cancer. Material and Method: Ninety controls and ninety LC patients were included in our study. Total RNA isolation was performed in peripheral blood mononuclear cells (PBMC) isolated from whole blood collected with ETDA; miRNA expressions were evaluated with qRT-PCR (quantitative Real Time-PCR). Results were evaluated by appropriate statistical methods. Results: We evaluated the effect of miR200b and miR1274a expression levels on lung cancer risk and found decreased levels of these miRNA expression levels in lung cancer (p=0.005 and p=0.021). Discussion: We conclude that miR200b and miR1274a have a tumor suppressor function in lung cancer.