Purpose: To evaluate efficacy of cone-beam CT–based liver perfusion mapping obtained immediately following conventional transarterial chemoembolization of hepatocellular carcinoma (HCC) for assessing tumor vascularity, technical success of chemoembolization, and treatment response. Materials and Methods: From July 2015 to June 2016, 35 patients with 57 HCCs who underwent cone-beam CT with post-processing software via conventional transarterial chemoembolization for HCC and follow-up examination were included. Three reviewers evaluated technical success on angiography, unenhanced cone-beam CT, contrast-enhanced cone-beam CT, and cone-beam CT–based liver perfusion mapping after transarterial chemoembolization per tumor and per patient. Parenchymal blood volume (PBV) was measured. Treatment response was determined on follow-up CT, MR imaging, or histopathology according to modified Response Evaluation Criteria In Solid Tumors. Diagnostic performance for detection of a viable tumor was evaluated using multiple logistic regression with C-statistics. Results: Treatment response was 38, 17, 2, and 0 for complete response, partial response, stable disease, and progressive disease per tumor and 18, 15, 2, and 0 per patient. In multiple logistic regression, unenhanced cone-beam CT, contrast-enhanced cone-beam CT, cone-beam CT–based liver perfusion mapping, mean value of PBV, and maximum value of PBV of tumor were significant in response assessment for per tumor and per patient (per tumor, all P <.001; per patient, P =.015, P =.001, P <.001, P =.020, and P =.032). Mean value of PBV of tumor was excellent for evaluating technical success with the highest C-statistic (0.880 and 0.920 for per tumor and per patient), followed by that of visual assessment of cone-beam CT–based liver perfusion mapping (0.864 and 0.908). Conclusions: Cone-beam CT–based liver perfusion mapping provided reliable images to evaluate technical success after transarterial chemoembolization of HCC by qualitative visual assessment and quantitative perfusion values.