We describe a case of duodenal varices successfully treated with balloon-occluded retrograde transvenous obliteration (BRTO) alone. A 63-year-old man presented with tarry stools. Computed tomography demonstrated dilated varices around the duodenum. Emergency endoscopic examination revealed varices of the second portion of the duodenum without active bleeding. There was no evidence of bleeding in the esophagus or stomach. Colonoscopy revealed no bleeding sites in the colon. On the day after admission, a superior mesenteric arteriogram obtained in the venous phase demonstrated a collateral vein from the inferior pancreaticoduodenal vein to the inferior vena cava. Retrograde venography performed via the right femoral vein confirmed that the right inferior adrenal vein was the draining vein and that the collateral vein was occluded. There were no tarry stools after BRTO. The patient was discharged 7 days after BRTO. Two months after discharge, computed tomography showed no dilated varices around the duodenum. Three months after discharge, endoscopy confirmed the absence of varices. No bleeding has been detected as of 10 months after discharge. We conclude that BRTO is an effective treatment for duodenal varices.