The terminal ileum which is too far from both the mouth and the anus to be observed endoscopically, remained the last place to be visualized by gastroenterological endoscopy. It has become possible to observe the entire colon owing to the advance in the fibercolonoscope, but the existence of the ileocecal valve prevented the introduction of the fibercolonoscope into the terminal ileum. Observing many ileocecal valves it was confirmed that the orifice of the valve was not always closed but it opened according to the intestinal movement. So it was thought possible to pass the valve when it opened maximally. Here we report the way of insertion of the scope into the terminal ileum, together with the normal and the pathologic condition of the ileal mucosa.