Screening for lung cancer has become a reality in certain countries, most notably the United States, but its implementation currently is under discussion and not established in many nations, including France. Screening for lung cancer currently is proposed using a low-dose computed tomography scanner. However, this approach lacks sensitivity and specificity, and could be improved when combined with a blood test (so-called "liquid biopsy"). Such tests attempt to detect biomarker (s) of early cancer development. Thus, numerous studies performed within the last few years have examined different blood components including circulating tumor cells and free DNA and other circulating elements such as microRNAs, exosomes, antibodies, and proteins. Recent studies have highlighted the value of seeking a signature for the methylation of circulating free DNA, which can be specific for certain solid tumors, including lung carcinoma. The current study describes some recent developments in the use of liquid biopsies for the detection of early-stage lung cancers, even those that are not yet visible using a low-dose computed tomography scanner.