PURPOSE: The recent sorafenib versus radioembolization in advanced hepatocellular carcinoma (SARAH) and selective internal radiation therapy versus sorafenib in locally advanced hepatocellular carcinoma (SIRveNIB) trials showed no statistically significant difference in overall survival for randomization to selective internal radiotherapy (SIRT) versus sorafenib for locally advanced hepatocellular carcinoma, although SIRT was better tolerated. Given the high cost of both treatments, we investigated their comparative cost-effectiveness from a US healthcare sector perspective. PATIENTS AND METHODS: We constructed a state-transition microsimulation model to simulate patients allocated to SIRT versus sorafenib according to an intention-to-treat principle. Hazard rates of disease progression and death were based on pooled individual patient data generated from the SARAH and SIRveNIB trials' Kaplan-Meier curves. Inputs for adverse events, treatment adherence, and quality of life utility weights were derived from trial data as well. Costs were based on Medicare reimbursement rates and literature. We performed probabilistic sensitivity analysis and estimated costs and quality-adjusted life years (QALYs) over a 5-year time horizon. We evaluated sensitivity to uncertainty of key model parameters. RESULTS: Costs were $78,859 v $58,397 (difference $20,462; 95% uncertainty interval $14,444 to 27,205) and QALYs were 0.88 v 0.87 (difference 0.02, -0.02 to 0.05) for sorafenib versus SIRT, respectively. The incremental cost-effectiveness ratio (ICER) of sorafenib was $1,280,224/QALY. The likelihood that sorafenib would be cost effective did not exceed 1%, assuming cost-effectiveness thresholds up to $200k/QALY. If the monthly price of sorafenib decreased from $16,390 to below $7,000, the ICER of sorafenib fell below $200k/QALY, and an ICER < $100k/QALY was reached if the monthly price fell below $6,600. CONCLUSION: Sorafenib is unlikely to provide a gain in quality-adjusted survival compared with SIRT at an acceptable cost for the US healthcare sector. Only if the current price decreased by more than 50% would sorafenib be considered economically attractive.