Objective <p>Many patients with lung cancer have cancer cachexia, which may result in complications and affect prognosis; however, its preoperative prevalence is unknown. Skeletal muscle mass loss after lung cancer surgery also affects prognosis. Although cachexia and sarcopenia share some similarities, whether preoperative cachexia affects postoperative sarcopenia is still unknown. Thus, we designed a cohort study of patients with non-small cell lung cancer (NSCLC) to investigate this.</p> Research methods and procedures <p>Patients with NSCLC who underwent surgery and perioperative rehabilitation were included in this study. The prevalence of preoperative cachexia and the association between preoperative cachexia and sarcopenia 1&#xa0;month after surgery were tested using propensity-score matching. After matching, the regression analysis was performed to investigate whether preoperative cachexia was independently related to sarcopenia 1&#xa0;month postoperatively.</p> Results <p>In total, 126 patients (73 men) median age 71 (interquartile range 67, 76) years were included in the study. Preoperative cachexia was present in 16 (12.7%) patients, and postoperative sarcopenia was present in 29 (23%) patients. Among the 126 patients, 16 and 32 patients were included in the preoperative cachexia and control groups, respectively, as a result of matching (standardized mean difference &lt; 0.1). After matching, regression analysis showed that preoperative cachexia was independently associated with sarcopenia at 1&#xa0;month postoperatively (odds ratio 4.33, <i>p</i> = 0.020).</p> Conclusions <p>Among the patients with NSCLC, 12.7% had preoperative cachexia. Preoperative cachexia in patients with NSCLC affected sarcopenia 1&#xa0;month postoperatively.</p>