Purpose: Retroperitoneal sarcomas (RPS) are rare, aggressive malignancies often requiring radical en bloc multivisceral resection. Major vascular involvement is a key determinant of resectability and may necessitate vascular reconstruction. This study describes patterns and outcomes of vascular reconstruction in RPS surgery at a high-volume sarcoma centre. Methodology: A retrospective review of primary RPS resections (2010–2022) was conducted at the State Sarcoma Service, Sir Charles Gairdner Hospital, Western Australia. Data included tumour type, vascular reconstruction, operative duration, length of stay, reoperation, readmission, mortality, and graft patency. Analyses included chi-squared testing and binary logistic regression. Results: A total of 129 patients underwent resection (mean age 58.6 years; 51% female). Vascular surgeons were involved in 76% of cases, and 30 patients (23%) required vascular reconstruction. Venous reconstruction was more common than arterial (20.2% vs 10.9%), most frequently associated with leiomyosarcoma and dedifferentiated liposarcoma, respectively. ECMO bypass was used in 22 cases (17.1%), exclusively for venous reconstruction. Inpatient and 1-year mortality were 2.3% and 9.3%, respectively. Increasing age was associated with higher 1-year mortality (OR 1.1 per year, p=0.009). Vascular reconstruction was associated with longer operative time (623 vs 360 minutes, p<0.001) and longer hospital stay (15 vs 12.5 days, p=0.02), but not with increased reoperation, readmission, or 1-year mortality. Conclusion: Vascular reconstruction is required in approximately one in five RPS resections and increases operative complexity and length of stay without adversely affecting short-term morbidity or 1-year mortality. These findings support the safety of aggressive oncovascular resection in a high-volume setting and highlight the role of multidisciplinary vascular involvement and adjuncts such as ECMO bypass in selected cases.