The aims of this study were to evaluate the frequency of dose-limiting toxicities and to find the recommended dose of combination chemotherapy with sorafenib and transcatheter arterial infusion (TAI) using cisplatin for patients with advanced hepatocellular carcinoma (HCC), for whom surgical resection, local ablation therapy, or transcatheter arterial chemoembolization were not indicated. Patients received 800 mg sorafenib daily. Cisplatin was given at one of three dosages (level 1, 35 mg/m2/cycle; level 2, 50 mg/m2/cycle; and level 3, 65 mg/m2/cycle) from feeding arteries to the HCC. The treatment was repeated every 4–6 weeks up to a maximum of six cycles, until there were signs of tumor progression or unacceptable toxicity. The dose-limiting toxicities experienced by the 20 enrolled patients were grade 4 increased aspartate aminotransferase at level 1, grade 3 gastrointestinal hemorrhaging at level 1, and grade 3 hypertension at level 3. The common drug-related adverse events that were of severity grade 3 or 4 included the elevation of aspartate aminotransferase (30%), alanine aminotransferase (20%), amylase (30%), and lipase (30%). Partial response was seen in four patients (20%), and 13 patients (65%) had stable disease. The median overall survival and progression-free survival were 9.1 and 3.3 months, respectively. The combination of sorafenib at 800 mg/day with TAI of cisplatin at 65 mg/m2/cycle was determined to be the recommended regimen. A randomized phase II trial of sorafenib alone versus sorafenib plus TAI of cisplatin is currently underway. This study was registered at UMIN as trial number UMIN000001496.