Sarcopenia, defined as decreased muscle mass and function, correlates with postoperative morbidity and mortality in cancer surgery. However, sarcopenia's impact specifically following robotic gastrectomy for gastric cancer has not been clearly defined. This study aimed to determine the influence of sarcopenia on short- and long-term clinical outcomes after robotic gastrectomy for gastric cancer.This retrospective study analyzed 381 gastric cancer patients undergoing robotic gastrectomy. Sarcopenia was diagnosed by preoperative computed tomography (CT) body composition analysis. Propensity score matching created 147 pairs of sarcopenia and nonsarcopenia patients for comparison. Outcomes included postoperative complications, survival, inflammatory markers, length of stay, intensive care unit (ICU) transfer, and readmissions.Sarcopenia patients exhibited significantly higher rates of overall (53.7% versus 21.1%, P < 0.001), serious (12.9% versus 4.1%, P = 0.007), and grade III-IV complications compared to nonsarcopenia pairs after matching. Sarcopenia independently predicted reduced 3-years overall (HR = 2.53, 95% CI: 1.19-5.40, P = 0.016) and disease-free survival (HR = 1.99, 95% CI: 1.09-3.66, P = 0.026). Sarcopenia patients also showed heightened postoperative leukocyte, neutrophil, platelet, platelet to lymphocyte ratio (PLR), systemic immune-inflammation index (SII), and monocyte to lymphocyte ratio (MLR) levels alongside suppressed lymphocytes, monocytes, and neutrophil to lymphocyte ratio (NLR).Preoperative sarcopenia is correlated with increased postoperative complications and poorer long-term survival in gastric cancer patients undergoing robotic gastrectomy. Sarcopenia assessment can optimize preoperative risk stratification and perioperative management in this population.Copyright © 2024 Elsevier Inc. All rights reserved.