Purpose <p>Adhesive small bowel obstruction is a significant complication following gastric cancer surgery; however, its long-term incidence and risk factors remain unclear. This study aimed to clarify the incidence and risk factors for adhesive small bowel obstruction after gastric cancer resection based on long-term follow-up data.</p> Methods <p>We conducted a retrospective cohort study of 2,738 patients who underwent radical gastrectomy for gastric cancer at our institution between January 1993 and December 2022. The development of adhesive small bowel obstruction was set as the endpoint. The association with clinical factors was evaluated using the Kaplan-Meier method and Cox proportional hazards regression analysis.</p> Results <p>During a median follow-up period of 5.8 years (interquartile range 2.4–11.7 years), 195 patients (7.1%) developed adhesive small bowel obstruction. Among them, 69 cases (35.4%) were reported within the first year after surgery, whereas 31 cases (15.9%) developed after 10 years. Multivariate analysis identified ileus during hospitalization, open surgical approach (hazards ratio [HR] 2.16), male sex, blood loss ≥ 224 mL, and history of abdominal surgery as independent risk factors (HRs: 2.86, 2.16, 1.93, 1.89, and 1.46, respectively).</p> Conclusion <p>Adhesive small bowel obstruction after gastric cancer surgery can develop beyond the conventional 5-year follow-up period, and the risk persists even after 10 years. Minimizing surgical invasiveness through laparoscopic approaches and reduced blood loss may lower the risk of adhesive small bowel obstruction.</p>