Functional dyspepsia (FD) is a complex disease reaction that occurs due to the presence of various factors, and its pathophysiology has not been clearly understood yet. FD is a diagnosis of exclusion after ruling out organic diseases. Therefore, the main treatments are limited to relieving symptoms through supportive care. The international prevalence of FD based on the Rome I criteria is approximately 25%. In Korea, there are very omnifarious symptoms in gastrointestinal disorders, and the medical vocabularies that describe the diagnostic standard are not closely associated with the daily vocabularies., Thus there would be a lot of restrictions in direct application of the Rome II criteria. However, the Korean Society of Gastrointestinal Motility had decided to promote the use of the international standardized Rome II criteria to be comparable to the clinical studies from other nations. There should be more extensive studies to differentiate the definitions of symptoms in Korea from those in other countries. The extended researches concerning the pathophysiology of FD are needed to find reliable treatment modalities for the disease.