The purpose of our cohort study was to investigate the effects of pleural adhesions on perioperative outcomes in patients undergoing video-assisted thoracoscopic surgery (VATS) lobectomy for non-small-cell lung cancer (NSCLC). We performed a single-center retrospective analysis on the prospectively-maintained dataset at our unit from February 2014 to November 2015. Patients were divided into two groups (Group A: presence of pleural adhesions; Group B: absence of pleural adhesions) according to our grading system of pleural adhesions when entering the chest cavity. Demographic differences in perioperative outcomes between these two groups were initially estimated. A multivariate logistic-regression analysis was then performed to confirm the predictive value of the presence of pleural adhesions. A total of 593 NSCLC patients undergoing VATS lobectomy were enrolled. The conversion and postoperative morbidity rates were 3.2% and 29.2%, respectively. There were 154 patients with pleural adhesions (Group A) and 439 patients without pleural adhesions (Group B). Group A patients had significantly higher rates of conversion to thoracotomy (9.1% vs. 1.1%; P<0.001) and surgical complications (24.0% vs. 14.4%; P=0.006) than those of Group B patients. No significant difference was found in the overall morbidity and cardiopulmonary complication rates between these two groups. The presence of pleural adhesions was also significantly associated with the prolonged length of chest tube drainage (log-rank P<0.001) and length of stay (log-rank P=0.032). Finally, the presence of pleural adhesions was identified as an independent risk factor for conversion to thoracotomy [odds ratio (OR) =5.49; P=0.003] and surgical complications (OR =1.94; P=0.033) by multivariate logistic-regression analyses. Presence of pleural adhesions can predict conversion to thoracotomy and postoperative surgical complications in patients undergoing VATS lobectomy for NSCLC. Our study calls for an internationally accepted grading system for the presence of pleural adhesions to stratify the surgical risk.