To evaluate the pathophysiology of irritable bowel syndrome, we have to know how to examine gut motility and visceral sensation. Examination for gastrointestinal (GI) motility disorders and abnormality of viscerosensory sensation originated from GI tract to the brain should be performed to evaluate pathophysiology of irritable bowel syndrome. GI dysmotility is detected by intraluminal pressure recording, and abnormality of GI sensation could be detected by barostat method. Recent advance is showing that functional MRI imaging may have a big impact on clarification of the pathophysiology of irritable bowel syndrome.