Objective <p>Video-assisted thoracic surgery (VATS) is a widely employed technique, with postoperative pneumonia (POP) being the primary complication following thoracoscopic lobectomy. The objective of this study is to investigate the association between preoperative fasting duration and the occurrence of postoperative pneumonia.</p> Methods <p>The patients who underwent VATS at Leshan City People’s Hospital from May 2019 to May 2023 were retrospectively analyzed in this study. Univariate and multivariate logistic regression analyses were conducted to identify the risk factors associated with postoperative pneumonia. Additionally, an independent sample t-test was performed to investigate the correlation between preoperative fasting time and postoperative pneumonia.</p> Results <p>The incidence of POP after thoracoscopic lung resection was found to be 9.9%. Risk factors for postoperative pneumonia include preoperative fasting time, smoking history, longer operation duration, BMI ≥ 24&#xa0;kg/m², and an elevated preoperative lymphocyte absolute value. Additionally, preoperative fasting time is negatively correlated with the incidence of postoperative pneumonia.</p> Conclusions <p>In this retrospective study, modestly longer preoperative fasting time was independently associated with a lower risk of postoperative pneumonia after thoracoscopic lobectomy. These findings generate a hypothesis that requires prospective validation.</p> Trial registration <p>This was a single-center retrospective trial that was registered at the Chinese Clinical Trial Center on April 24, 2024. The registration number of this study is ChiCTR2400083410.</p>