Background Pancreatic head ductal adenocarcinoma (PHDAC) patients with the same tumor-node-metastasis (TNM) stage may share different outcomes after pancreaticoduodenectomy (PD). Therefore, a novel method to identify patients with poor prognosis after PD is urgently needed. We aimed to develop a nomogram to estimate survival in PHDAC after PD.</p> Methods To estimate survival after PD, a nomogram was developed using the Tongji Pancreatic cancer cohort comprising 355 PHDAC patients who underwent PD. The nomogram was validated under the same conditions in another cohort (N = 161) from the National Taiwan University Hospital. Prognostic factors were assessed using LASSO and multivariate Cox regression models. The nomogram was internally validated using bootstrap resampling and then externally validated. Performance was assessed using concordance index (c-index) and calibration curve. Clinical utility was evaluated using decision curve analysis (DCA), X-tile program, and Kaplan-Meier curve in both training and validation cohorts.</p> Results Overall, the median follow-up duration was 32.17 months, with 199 deaths (64.82%) in the training cohort. Variables included in the nomogram were age, preoperative CA 19-9 levels, adjuvant chemotherapy, Tongji classification, T stage, N stage, and differentiation degree. Harrell's c-indices in the internal and external validation cohorts were 0.79 (95% confidence interval [CI], 0.76-0.82) and 0.83 (95% CI, 0.78-0.87), respectively, which were higher than those in other staging systems. DCA showed better clinical utility.</p> Conclusion The nomogram was better than TNM stage and Tongji classification in predicting PHDAC patients' prognosis and may improve prognosis-based selection of patients who would benefit from PD.</p>