Background and aimsSurgical planning in liver resection depends on the precise understanding of the three-dimensional (3D) relation of tumors to the intrahepatic vascular trees. This study aimed to investigate the impact of 3D printing (3DP) technology on the understanding of surgical liver anatomy.MethodsWe selected four hepatic tumors that were previously resected. For each tumor, a virtual 3D reconstruction (VIR) model was created from multi-detector computed tomography (MDCT) and was prototyped using a 3D printer. Forty-five surgical residents were evenly assigned to each group (3DP, VIR, and MDCT groups). After evaluation of the MDCT scans, VIR model, or 3DP model of each tumor, surgical residents were asked to assign hepatic tumor locations and state surgical resection proposals. The time used to specify the tumor location was recorded. The correct responses and time spent were compared between the three groups.ResultsThe assignment of tumor location improved steadily from MDCT, to VIR, and to 3DP, with a mean score of 34.50, 55.25, and 80.92, respectively. These scores were out of 100 points. The 3DP group had significantly higher scores compared with other groups (p<0.001). Furthermore, 3DP significantly improved the accuracy of surgical resection proposal (p<0.001). The mean accuracy of the surgical resection proposal for 3DP, VIR, and MDCT was 57, 25, and 25%, respectively. The 3DP group took significantly less time, compared with other groups (p<0.005). The mean time spent on assessing the tumor location for 3DP, VIR, and MDCT groups was 93, 223, and 286s, respectively.Conclusions3D printing improves the understanding of surgical liver anatomy for surgical residents. The improved comprehension of liver anatomy may facilitate laparoscopy or open liver resection.