Surgical treatment for internal fistula is rarely indicated for terminally ill patients with cancer because of their poor prognoses. Reports of surgical or pharmacologic treatment of vesicoenteric fistula in terminally ill patients with cancer are rare. A 73-year-old woman with rectal cancer that had directly invaded the bladder and metastasized to the liver was admitted to our hospital with high fever and severe perineal pain. Retrograde urography indicated an enterovesical fistula. Although the urinary tract infection was treatable with antibiotics, frequent episodic pain, due to urethritis secondary to the fistula, was not alleviated with opioid and topical treatment. Three days after starting octreotide 0.3 mg/d, the severe pain was alleviated, and follow-up retrograde urography revealed closure of the fistula. This suggests that treatment with octreotide may have enabled closure of the fistula. Thus, octreotide should be considered a viable therapeutic option in terminally ill patients with inoperable internal fistula.