Obesity is prevalent in Korea. An increase in food intake and a decrease in energy expenditure are responsible for obesity. Gut hormones play a role in controlling food intake. Obesity is suggested to be linked to common gastrointestinal functional disorders. Obesity is associated with an increased risk of gastroesophageal reflux disease, Barrett esophagus and esophageal adenocarcinoma. Epidemiologic studies indicate that obesity is associated with chronic gastrointestinal symptoms. This association suggests the possibility that obesity and functional gastrointestinal disorders may be pathophysiologically linked. However, data on the relationship between obesity and functional gastrointestinal disorders are inconsistent. In this paper, we review the role of gastrointestinal hormones in food intake and the relationship between obesity and functional gastrointestinal disorders.