https://www.selleckchem.com/products/gdc-0068.html Chronic obstructive pulmonary disease (COPD) is known to be a risk factor of pneumonia after esophagectomy. In this study, we investigated the relationship of airflow limitation with the occurrence and the severity of pneumonia in esophageal cancer patients who underwent esophagectomy. We enrolled 844 patients who underwent curative esophagectomy between 2009 and 2018. The airflow limitation was evaluated using the percent-predicted forced expiratory volume at 1s (%FEV1) with spirometry. There were 597 (70.7%), 141 (16.7%), 68 (8.1%), and 38 patients (4.5%) with %FEV1 of ≥ 90%, 80-90%, 70-80%, and < 70% categories, respectively. One hundred and ninety-one patients (22.6%) occurred pneumonia, and the incidences of pneumonia in each category of patients were 18.8%, 28.4%, 29.4%, and 50.0%, respectively. In multivariate analysis, the categories of 80%-90%, 70-80%, and < 70% were significantly associated with a higher incidence of postoperative pneumonia (OR 1.57; 95% CI 1.02-2.43, OR 1.87; 95% CI 1.04-3.36, OR 3.34; 95% CI 1.66-6.71, respectively), with the %FEV1 category of ≥ 90% as reference. The incidence of severe pneumonia of Clavien-Dindo grade III or higher was also significantly associated with the %FEV1. In patients without COPD, the incidence of pneumonia was significantly higher in those with %FEV1 < 90% than in those with %FEV1 ≥ 90% (32.2% versus 17.5%, p < 0.001). The airflow limitation can help predict the occurrence of pneumonia after esophagectomy in patients with and without COPD. Exclusive preventive measures should be considered in patients with reduced %FEV1 undergoing esophagectomy. The airflow limitation can help predict the occurrence of pneumonia after esophagectomy in patients with and without COPD. Exclusive preventive measures should be considered in patients with reduced %FEV1 undergoing esophagectomy. Future navy officers require unique training for emergency medical response in the isolat