AimThis study aimed to comprehensively assess the incidence of immune‐related adverse events (irAEs) and the detection systems in place for patients with liver cancer undergoing treatment with immune checkpoint inhibitors (ICIs), using a self‐administered anonymous questionnaire. The questionnaire was designed to gather crucial insights into the management of irAEs in these patients.MethodsA self‐administered anonymous questionnaire was sent to 456 liver disease collaborative base hospitals and cancer care coordination base hospitals in Japan.ResultsResponses were received from 112 facilities, indicating a response rate of 25%. The region with the highest response rate was Kanto (22%, 24 sites), followed by Kyushu (19%, 21 sites), Chubu (14%, 15 sites), and Kinki (14%, 15 sites). The number of patients with hepatocellular carcinoma (HCC) who received ICI treatment varied, with a mean ± SD of 20.4 ± 19.4 cases per year per facility. The number of full‐time physicians who provided ICI treatment for HCC was 4.2 ± 3.3 (mean ± SD), ranging from 0 to 24 per facility. Of these, the majority included hepatologists and oncologists, whose numbers were 3.3 ± 2.4 (mean ± SD) (range, 0–11) and 0.8 ± 1.0 (0–3), respectively. Gastroenterologists and internal medicine specialists participated in the treatment at some facilities.ConclusionsThe survey results revealed that physicians administered ICI therapy for an average of 20 HCC cases per institution, with more than 17 types of irAEs reported. The most common irAEs were hepatic dysfunction, followed by thyroid dysfunction, skin disorders, interstitial pneumonia, and renal dysfunction.