Purpose To assess the feasibility of performing same-day vascular flow redistribution and Yttrium-90 radioembolization (90Y-RE) for hepatic malignancies. Materials and Methods From November 2015 to February 2019, patients undergoing same-day hepatic flow redistribution during work-up angiography,(99m)Technetium-labeled macroaggregated albumin (Tc-99m-MAA) SPECT/CT and 90Y microsphere-RE, were recruited. Within 18 h following the delivery of 90Y resin microspheres, an 90Y-PET/CT study was performed. According to patients' vascular anatomy, flow redistribution was performed by microcoil embolization of extrahepatic branches (group A), intrahepatic non-tumoral vessels (group B) and intrahepatic tumoral arteries (group C). The accumulation of(99m)Tc-MAA particles and microspheres in the redistributed areas was qualitatively evaluated using a 5-point visual scale (grade 1 = < 25% accumulation; grade 5 = 100% accumulation). Differences in the distribution of microspheres among groups were assessed with Mann-WhitneyUtest. Results Twenty-two patients were treated for primary (n = 17) and secondary (n = 5) hepatic malignancies. The MAA-SPECT/CT showed uptake in all the redistributed areas. Regarding the accumulation of microspheres within the redistributed segments in all the groups, perfusion patterns were classified as 2 in 1 case, 4 in 6 cases and 5 in 15 cases. No statistically significant differences were observed between groups A and B-C (Uvalue = 34,p = 0.32) and between groups B and C (Uvalue = 26,p = 0.7). Mean predicted absorbed doses by the tumoral and normal hepatic tissues were 163.5 +/- 131.2 Gy and 60.4 +/- 69.3 Gy, respectively. Mean total procedure time (from work-up angiography to 90Y delivery) was 401 +/- 0.055 min. Conclusion Performing same-day redistribution of the arterial hepatic flow to the target and 90Y-microsphere delivery is feasible in the treatment of liver tumors. Clinical Trials RegistryNCT03380130.