A 40-year-old woman with ulcerative colitis (UC) was admitted to our hospital because of diminution of consciousness and left palsy. UC had been diagnosed 6 years before, but had not been treated. MRI revealed complete obstruction of the superior sagittal sinus. Cerebral sinus thrombosis, as a complication of UC, was diagnosed. We started anticoagulant therapy, but she passed away 5 days later. UC has been reported to show hypercoagulation status, leading to deep vein thrombosis within the body which sometimes causes pulmonary infarction, but occurrence of cerebral sinus thrombosis is rare.