Background/AimPresently, there are no therapeutic options for unresectable hepatocellular carcinoma (u‐HCC) patients who are intolerant to sorafenib or regorafenib failure. There have been no reports with detailed clinical findings of lenvatinib (LEN), a newly developed first‐line tyrosine kinase inhibitor (TKI), obtained in real‐world practice. We aimed to elucidate the therapeutic efficacy of LEN.Materials/MethodsFrom March to August 2018, 105 u‐HCC patients were treated with LEN. Following exclusion of those who started with a reduced LEN dose and/or had a short observation period (<2 weeks), 77 patients (72.0 ± 8.9 years, 59 males, 8 mg/12 mg = 49/28, Liver Cancer Study Group of Japan 6th [LCSGJ]‐TNM stage II/III/IVa/IVb = 8/28/4/37, and American Joint Committee on Cancer/Union for International Cancer Control 8th [AJCC/UICC]‐TNM stage IB:II:IIIA:IIIB:IVA:IVB = 2:27:6:5:9:28) were divided into two groups (TKI naïve [n = 33] and TKI experienced [n = 44], including 11 with regorafenib history). Therapeutic response was evaluated using mRECIST. Clinical data were retrospectively evaluated.ResultsThere were significant differences in age (74.6 ± 11.2 vs 70.0 ± 5.9 years, P = 0.040), LCSGJ‐TNM (II:III:IVa:IVb = 8:12:1:12 vs 0:16:3:25, P = 0.006), and AJCC/UICC‐TNM (IB:II:IIIA:IIIB:IVA:IVB = 2:17:1:1:4:8 vs 0:10:5:4:5:20, P = 0.028), while hepatic reserve function, adverse event (AE) profiles, and progression‐free survival (89.7%/80.4% vs 90.5%/80.1%, P = 0.499) and overall survival (96.7%/96.7% vs 100%/92.3%, P = 0.769) after 4 and 12 weeks were not significantly different between the TKI‐naïve and TKI‐experienced groups. Overall response rate and disease control rate at 4 weeks (n = 52) were 38.5% and 80.8%, respectively, and 32.4% and 70.3%, respectively, at 12 weeks (n = 37). A significant decline in log10 AFP from the baseline to 4 weeks after introducing LEN was observed in patients with PR and SD (2.047 ± 1.148 vs 1.796 ± 1.179, P < 0.001).ConclusionRegardless of past TKI therapy, therapeutic response and AEs after introducing LEN were similar. LEN may be an important treatment for the present unmet need regarding TKI treatment against u‐HCC.