Tumor infiltrating lymphocytes (TIL) and peripheral blood lymphocytes (PBL) were isolated from 5 patients with multiple hepatocellular carcinoma (HCC) and with metastatic liver tumor. Proliferation of lymphocytes was observed following addition of interleukin-2 (700 JRU/ml) into the culture media. After analysis of LAK cells by FACS, the antitumor activities were examined. Higher levels of cytotoxic activity against tumor cells (K 562 and Daudi) have continued during the culture period ranging from 2 to 5 weeks. Adoptive immunotherapy was performed using TIL-LAK and PBL-LAK via hepatic artery for three patients with HCC and one patient with metastatic tumor. The average number of administered lymphocytes was 1 x 10(9). Reduction of tumor size was observed after this therapy, which caused no severe side effects exclusive of high fever and pleural effusion. Our results indicate that the treatment using lymphokine activated killer cells and interleukin-2 may be a promising modality for patients with multiple HCC.