The aims of the present study were to examine whether unresectable hepatocellular carcinoma (HCC) patients treated with initial dose of sorafenib of 400 mg/day (half-dose group) had comparable treatment efficacy, safety and survival merit as compared with those treated with initial dose of sorafenib of 800 mg/day (standard-dose group) in a multicenter large study. For reducing the bias in patient selection, we compared clinical outcomes of these two groups using propensity score matching analysis. A total of 465 patients were treated with sorafenib at fourteen hospitals in Japanese Red Cross Liver Study Group from 2008 to 2013. After propensity score matching, 139 matched HCC patients were selected for analysis in both groups. We retrospectively compared overall survival (OS), progression-free survival (PFS), best treatment response and sorafenib related serious adverse events (SAEs) in the two groups. There were no relevant differences in terms of OS (median OS intervals: 9.2 months in the standard-dose group and 9.7 months in the half‑dose group, P=0.350), PFS (median PFS intervals: 3.4 months in the standard-dose group and 3.2 months in the half-dose group, P=0.729) and best treatment efficacy (objective response rate: P=0.416; disease control rate: P=0.719). Grade 3 or more SAEs were observed in 37 patients (26.6%) in the standard-dose group and 33 patients (23.7%) in the half-dose group (P=0.580). Furthermore, in all subgroup analyses according to Child-Pugh classification and Barcelona Clinic Liver Cancer stage, there were no significant differences in the two groups. In conclusion, unresectable HCC patients treated with initial half‑dose sorafenib had comparable prognosis compared with those treated with initial standard-dose sorafenib.