A 50-year-old male with unresectable hepatocellular carcinoma (HCC) had a hypercalcemic crisis with a serum calcium concentration of 7.8 mEq/zeta, without any evidence for bone metastases or parathyroid lesions. The hypercalcemia was thought to be due to increased renal reabsorption of calcium and increased bone resorption, which was probably caused by humoral factors derived from the HCC, some being parathyroid hormone-like factors. Since conservative therapy for hypercalcemia was not sufficiently effective and was accompanied by progressive exacerbation of ascites and leg edema, transcatheter arterial chemo-embolization (TACE) was performed. On the following day, serum calcium concentration decreased from 6.3 mEq/zeta to the normal range, although serum alpha-fetoprotein levels decreased only slightly. Thereafter hypercalcemia did not develop for about 4 weeks. The results demonstrated that TACE can be effective for humoral hypercalcemia of HCC.