A 74-year-old man was admitted with primary complaints of appetite loss, abdominal swelling, and pedal edema. Laboratory data revealed the presence of anemia and hypoalbuminemia. Barium enema and colonofiberscopy demonstrated an advanced cancer in the transverse colon. Albumin scintigraphy revealed high uptake by the tumor in the transverse colon. Preoperative administration of albumin did not improve hypoalbuminemia. Serum protein and albumin levels improved immediately after resection of the tumor. Therefore, in the presence of hypoalbuminemia due to leakage from the tumor, it is important to operate promptly, without waiting to correct the hypoalbuminemia.