Functional gastrointestinal diseases, accompanied by prolonged abdominal pain, significantly affect on the patients’ quality of life, regardless of their age and gender. So far, the diagnosis of such disorders remains challenging. Currently there is no consensus on the type and number of tests to be performed, or on the age at which children should be examined. Chronic abdominal pain may mask functional gastrointestinal disorders as well as organic diseases of various organs and systems. The analysis of modern ideas about functional diseases of the digestive system, accompanied by abdominal pain, is carried out.