The authors report their study on gastro-esophageal reflux disease, a pathology that has become increasingly common over the past years reflecting both a real increase and the use of new and more sophisticated and reliable diagnostic methods and tests. It can be included in the group of pathologies absorbing the largest proportion of financial resources, even exceeding biliary lithiasic disease according to American studies. The authors start by analysing the symptoms of gastroesophageal reflux disease, drawing a distinction between typical (heartburn, epigastric pain and postprandial regurgitation) and atypical symptoms (laryngotracheal symptoms, bronchopulmonary symptoms and esophageal motor incoordination). They outline the diagnostic iter and tests most widely used today to achieve a correct diagnosis. Lastly, they report their experience of 160 patients attending their esophageal diagnostic unit since January 1999 who underwent a number of different instrumental tests, the results of which are compared. Three different aspects are compared: the presence of symptoms, 24-hour pH-metry and endoscopic tests. All these are necessary for a correct diagnosis of gastroesophageal reflux disease and to evaluate the possibility and efficacy of surgery. They emphasise the diagnostic importance of 24-hour pH-measurement as the only test that can directly reveal gastroesophageal reflux. Positive pH results represent a discriminating element in deciding whether the patient should undergo surgery.