Hepatocellular carcinoma may be unresectable for volumetric reasons. The future remaining liver after hepatectomy might be too small to ensure survival. Preoperative selective portal vein embolization of the tumorous lobe can induce hypertrophy of the future remaining liver and enable safer surgery. A 76-year-old patient with hepatocellular carcinoma needed right lobectomy however, the future remaining liver was judged insufficient to ensure an uneventful postoperative course. The left lobe to whole liver volumetric ratio was to small (29.7%) and a preoperative selective portal vein embolization of the right portal branch via a percutaneous, transhepatic, contralateral approach was performed without side effects. A Doppler estimation of left branch portal blood flow and velocity was carried out before and after preoperative selective portal vein embolization. After 21 days the left lobe volume increased by about 44.2% with a safe left lobe/whole liver ratio of 40.8%. The portal blood flow and portal blood flow velocity showed an increase of 253% and 122%, respectively. A right lobectomy was performed without complications. Three months later, computed tomography scan showed no hepatocellular carcinoma recurrence. Preoperative selective portal vein embolization is a safe technique which can enable major hepatectomy to be performed in situations otherwise judged unresectable for a life-threatening volumetric insufficiency. The portal blood flow and portal blood flow velocity evaluations can easily predict the hypertrophy rate of non-embolized liver segments.