The interhemispheric translamina terminalis approach has made total removal of a craniopharyngioma less risky. Nevertheless, one of the pitfalls of this approach is cutting of the draining veins combined with retraction. A case of craniopharyngioma in which a subcortical hematoma developed is reported. The divided draining veins and the 60-minute retraction period were thought to have caused this complication. We therefore determined the clinical effect of cutting the draining veins and retraction on the regional cerebral blood flow and the motor nerve action potential. There were marked changes and a hematoma occurred mostly when the veins were divided and retraction was applied over the area.