BACKGROUND: We aimed to investigate the characteristics and pretreatment risk factors for postoperative pulmonary complications (PPCs) after neoadjuvant concurrent chemoradiotherapy (CRTx) in patients with non-small cell lung cancer (NSCLC). METHODS: We retrospectively reviewed data of 122 patients who underwent curative resection after neoadjuvant CRTx for NSCLC between 2007 and December 2019. Clinical data, including pulmonary function and body mass index (BMI) at the time of concurrent CRTx initiation, were analyzed. We performed logistic regression analyses to identify the risk factors for PPCs and built a nomogram with significant factors. RESULTS: Of the 122 patients included (mean age, 60.1 +/- 9.7 years; 69.7% male), 27 experienced PPCs (severity grade >/= 2). The most common PPCs were pneumonia (n = 17). Patients with PPCs had a significantly longer hospital stay (median 6.0 vs. 17 days, p < 0.001) and a higher in-hospital mortality rate (1.1% vs. 29.6%, p < 0.001). In multivariable analysis, lower BMI (odds ratio [OR] 0.796, 95% confidence interval [CI] 0.628-0.987, p = 0.038), no comorbidity (OR 0.220, 95% CI: 0.059-0.819, p = 0.048), smoking history (OR 4.362, 95% CI: 1.210-15.720, p = 0.024), and %predicted DLCO <60% (OR 3.727, 95% CI: 1.319-10.530, p = 0.013) were independent risk factors for PPCs. The predictive accuracy of the nomogram built with factors was excellent (concordance index: 0.756). CONCLUSIONS: The nomogram constructed with factors identified in multivariable analysis could serve as a reliable tool for evaluating the risk of PPCs in the patients who underwent neoadjuvant CRTx for NSCLC.