Lung cancer is the most lethal malignancy in the world, and each year thousands of people die from this disease. Early detection has proven to increase the 5-year survival for this cancer in general, independent of the origination site in the lung. To address this challenge, we have used cell-based SELEX (Systematic Evolution of Ligands by Exponential Enrichment) to select a panel of aptamers capable of distinguishing lung adenocarcinoma cells from normal lung epithelial cells. These aptamers bind at physiological and formalin-fixed conditions and display affinity for their targets with apparent K(d')s in the nanomolar range. Our findings suggest that the selected aptamers have the potential to be used in clinical settings, as well as to improve classification of nonsurgical specimens, another current challenge in lung cancer.