Hypercalcemia is a common electrolyte imbalance in patients with malignancy. Approximately 80% of hypercalcemia is associated with humoral hypercalcemia of malignancy (HHM), but occurs rarely in colorectal carcinomas. A 72-year-old man was admitted with abdominal pain and bowel habit change. Colonoscopy showed a malignant tumor in the transverse colon. Laboratory data showed an elevated serum calcium level (11.6 mg/dL) and elevated parathyroid hormone-related peptide level (12.2 pmol/L). Histology showed poorly differentiated adenocarcinoma. We infused intravenous normal saline, furosemide and pamidronate. The serum calcium level was subsequently normalized. However, the patient died from cancer progression 10 days later. With a review of the relevant literature, we report a case of adenocarcinoma of the transverse colon with HHM. (Intest Res 2012;10:397-399)