Recently, subsegmental transcatheter hepatic arterial embolization under balloon occlusion of the corresponding hepatic vein has been performed to treat hepatic infarction in subregion hepatocellular carcinoma (HCC). Here, we report subsegmental transcatheter hepatic arterial embolization under balloon occlusion of the corresponding hepatic vein with styrene maleic acid neocarzinostatin lipiodol (SMANCS) (SMANCS-TAE under balloon occlusion of the corresponding hepatic vein). This study included 9 patients with HCC who underwent SMANCS-TAE under balloon occlusion of the corresponding hepatic vein. In all patients, the therapeutic effects (TE) were evaluated according to the criteria of direct response to liver cancer treatment on abdominal computed tomography (CT) 3 weeks after surgery. In 7 patients who could be followed for more than one year, there was no postoperative relapse at the site of treatment. Furthermore, this procedure facilitated the detection of accumulation of SMANCS not only in the tumor but also in the subregion of the tumor in patients with HCC involving immature arterial tumor neoplastic vessels. In patients with large HCC complicated by severe heart failure showing a poor general condition, this procedure allowed treatment to be completed without complication. SMANCS-TAE under balloon occlusion of the corresponding hepatic vein, which can also embolize the portal vein by applying targeting chemotherapy with SMANCS, may cause necrosis not only in the tumor but also in noncancerous liver tissues. This procedure may be an indication for a larger number of cases than standard TAE, facilitating more complete local treatment.