Widely used low dose helical thoracic computed tomography (CT) scan in screening results is detecting more and more small-sized lung cancers. Whether systematic lymph node (LN) dissection should be done or not on subcentimeter lung cancers still remains controversial. From June 2000 to December 2008, the records of all patients who underwent resection of primary non-small cell lung cancer (NSCLC) 1 cm or less in diameter were reviewed. LN metastases and lymphatic vessel invasion (LVI) were studied between different subgroups to determine the predictors of metastases. Of all 41 patients, there were 35 (85%) cases of adenocarcinoma, 3 (7%) cases of squamous cell carcinoma, 3 (7%) cases of other types. There were 6 (15%) cases with nodal metastases. Lymphatic invasion was found in 11 (27%) patients. Tumor differentiation, visceral pleural involvement, preoperative serum carcinoembryonic antigen (CEA), ground-glass opacity content on CT and blood vessel invasion (BVI) were significant predictors for both LN metastases and LVI. Systematic LN dissection is recommended for subcentimeter patients with good risk, however, if the patient is female, or with normal CEA, or with ground-glass opacity, or with Noguchi A or B type, surgeons might omit the procedure.