Purpose: Hepatopancreatobiliary (HPB) malignancies are among the most commonly diagnosed in Australia. However, major surgeries in this cohort are associated with significant risk and are highly morbid. Days Alive and at Home within 30 Days (DAH30) is a novel composite outcome measure accounting for the index admission, any healthcare readmissions, and deaths within 30 days. This study aimed to identify associations between peri-operative factors and DAH30 in patient undergoing surgery for HPB malignancies. Methodology: This retrospective cohort study included consecutive adult patients undergoing surgery for HPB malignancy at two major hospitals in Sydney, Australia between 2015 and 2022. Logistic linear regression models were used to evaluate the relationship between DAH30 scores and patient characteristics, surgical outcomes and re-admissions to ICU. Results: A total of 981 patients were included. For gastric and hepatobiliary surgeries, the median DAH30 score was 22 days, however for oesophageal and pancreatic procedures, the median DAH30 score were 11 and 15 days, respectively. Overall, increasing age (p<0.001), BMI (p<0.001), surgical time (p<0.001), ASA score (p=0.026), ICU length of stay (p<0.001) and ICU re-admission rate (p<0.001) were significant predictors of worse DAH30 scores. Conclusion: This large cohort study established DAH30 benchmarks for HPB cancer surgeries and identified key predictors of poorer outcomes, including increased age, BMI, surgical time, and ICU stays. These findings can guide preoperative optimisation strategies and inform shared decision-making to improve postoperative recovery and patient-centred outcomes in HPB cancer surgery.