Simulation and video-based assessment (VBA) offer residents the opportunity to develop operative skills while ensuring patient safety. This study aims to determine whether simulation training can predict residents' operative performance, focusing on the gastrojejunal (GJ) anastomosis during robotic pancreatoduodenectomy. Twenty-seven general surgery residents completed simulated robotic GJ drills and subsequently performed GJs in the operating room (OR). Both simulated and intraoperative performances were video recorded and retrospectively assessed by two blinded graders using the Objective Structural Assessment of Technical Skills (OSATS) scale, time to completion, and occurrence of errors. Intraoperative GJ OSATS scores were compared in cases with and without Clinically Relevant Delayed Gastric Emptying (CRDGE). Statistical analysis was performed using Spearman's rho, Chi-square, and Kruskal-Wallis tests. For simulated GJs, the median OSATS score was 29 (IQR 27-33), time to completion was 30min (IQR 27-35), and 11 cases had at least one error. Intraoperative GJs had a median OSATS of 30 (IQR 27-31), time to completion of 41min (IQR 36-51), and errors occurred in nine cases.The OSATS score on the simulated GJs demonstrated a significant positive correlation to the OSATS score on the operative GJs (r = 0.74; p < 0.001) and less time to completion (r = - 0.68; p < 0.001). A shorter simulated GJ completion time significantly correlated with a higher intraoperative OSATS score (r = - 0.52; p < 0.01). Residents with at least one error in the simulated GJs had lower OSATS scores and higher times intraoperatively. Those cases with CRDGE had significantly lower intraoperative OSATS scores than those without CRDGE. Performance on a simulated robotic GJ environment is a robust predictor of OR GJ performance, demonstrating predictive validity. VBA of residents' operative GJ performance is associated with the presentation of CRDGE. Simulation-based training may be crucial to optimizing surgical outcomes before operating on patients.