Objective To investigate the incidence and risk factors for unplanned hospital readmission within 30 days in gastric cancer patients who underwent curative gastrectomy and clarify the predictive value of nutritional risk screening 2002 NRS 2002 tool for unplanned readmission. Method This retrospective analysis included 312 patients who underwent curative gastrectomy for gastric cancer in Nanjing Hospital Affiliated to Nanjing Medical University between January 2016 and January 2022. The incidence and causes of unplanned readmission after curative gastrectomy for gastric cancer were analyzed. All patients were divided into readmission 26 and non-readmission 286 group and the distribution of baseline characteristics between the two groups was compared. The univariate and multivariate logistic regression analysis was conducted to identify the independent risk factors for unplanned readmission. Result According to the NRS 2002 scale 33. 0% 103 / 312 of gastric cancer patients were at risk of preoperative malnutrition NRS 2002 score ≥ 3 points . The unplanned readmission rate within 30 days was 8. 3% 26 / 312 for gastric cancer patients who underwent curative gastrectomy and the average time interval from discharge to readmission was 10. 8 ± 7. 4 days. Postoperative ileus 19. 2% 5 / 26 and intra-abdominal fluid collection / infection 15. 4% 4 / 26 were the main causes of hospital readmission. The univariate and multivariate logistic regression analysis demonstrated that NRS 2002 score ≥ 3 points OR = 3. 259 95% CI = 1. 357-7. 828 P= 0. 008 patient age ≥ 65 years OR= 3. 212 95%CI = 1. 256-8. 213 P= 0. 015 the presence of postoperative complications OR= 3. 407 95%CI = 1. 258-9. 226 P = 0. 016 and operation time ≥ 180 min OR= 2. 734 95%CI = 1. 108-6. 746 P= 0. 029 were independent risk factors for unplanned readmission in gastric cancer patients who underwent curative gastrectomy. Conclusion The NRS 2002 was an effective tool to predict unplanned readmission after curative gastrectomy for gastric cancer. This finding further emphasized the importance of optimizing preoperative nutritional status to improve the adverse perioperative outcomes.