Abstract: To evaluate the clinical significance of serum BCAR1 levels in non-small cell lung cancer ( NSCLC ) and pulmonary tuberculosis. Methods: An enzyme-linked immunosorbent assay ( ELISA ) was used to determine the serum BCAR1 levels in 65 patients with NSCLC, 26 with benign pulmonary tumors ( 15 inflammatory pseudotumors, 7 hamartomas, and 4 fibroid tumors ), 30 with pulmonary tuberculosis ( 17 tuberculomas and 13 cavitary pulmonary tuberculosis ), and 40 healthy volunteers who were admitted to the Daping Hospital, Chongqing, China between March 2009 and May 2010. Results: The serum BCAR1 levels were significantly higher in the NSCLC group than in the benign pulmonary tumor and the healthy control group ( P < 0.001 ). Nevertheless, there were no significant differences between the NSCLC group and the pulmonary tuberculosis group ( P > 0.05 ). The serum BCAR1 levels did not correlate with the age, gender, or lymph node metastasis ( P > 0.05 ). Although there were no significant differences in the serum BCAR1 levels between adenocarcinoma and squamous carcinoma ( P > 0.05 ), the serum BCAR1 levels were significantly lower in the cases with bronchioloalveolar carcinoma than with the other subtypes of NSCLCs ( P = 0.02 ). The serum BCAR1 levels were gradually increased with the progression of tumor staging and then was decreased after the removal of the tumors. The serum BCAR1 levels were obviously higher in the pulmonary tuberculosis group than in the benign pulmonary tumors group and the healthy controls ( P < 0.001 ) and were positively correlated with the diameter of the tuberculosis lesion ( rs = 0.92, P < 0.001 ). The serum BCAR1 levels  were decreased after the removal of the tuberculous lesions. The serum BCAR1 levels were higher in the cavitary pulmonary tuberculosis group than in the tuberculoma group ( P < 0.001 ). There were no appreciable differences in the serum BCAR1 levels between the benign pulmonary tumor group and the healthy controls ( P > 0.05 ). Conclusion: Serum BCAR1 can be used as a marker for diagnosing and assessing the progression of NSCLC, as well as determining the therapeutic efficacy of treatment for NSCLC and pulmonary tuberculosis.