Abstract: Lung cancer is the most common cancer worldwide, accounting for approximately 18% of all cancer-related deaths.Circulating tumor cells(CTCs) have the capacity to spread into the blood stream.This capacity of CTCs is one of the most critical factors for unfavorable clinical outcome of patients with NSCLC.Detection of CTCs using a simple blood test may assist in early detection of lung cancer.Researchers have attempted to isolate CTCs from peripheral blood using various techniques.Although reports on CTC detection are abundant, methodological aspects concerning sensitivity, specificity, and reproducibility have prevented a clear appraisal of the clinical impact.This paper gives a brief description of each CTC detection method.