Recent experiences indicate that, as already reported for other types of cancer, circulating tumor cells (CTCs) may play a role also in non small cell lung cancer (NSCLC) for diagnosis, therapy monitoring and prognostic purposes. CTCs evaluation could be particularly relevant in this clinical setting not only for the objective difficulty in obtaining tumor tissue, but also because of the lack of reliable tumor markers. In the current review, we Will focus on the possible applications of CTCs in NSCLC patients. (C) 2016 Elsevier Ireland Ltd. All rights reserved.