Today, it is difficult to set a correct definition and diagnosis of gastroesophageal reflux disease. The attempt to define it on the basis of "typical" symptoms, like heartburn and regurgitation, or "atypical" symptoms, like chronic cough, asthma, hoarseness and thoracic pain, or on the basis of endoscopic esophagitis presents notable difficulties. Moreover, the problem of a correct definition is tightly tied up to the ability to set a correct and early diagnosis. There are many diagnostics tools, but none of them is the golden standard. Today, the trend is to emphasize the role of the 24-hour pH-monitoring in diagnosing the reflux in those symptomatic patients with no visible esophagitis. However, its limit is to underline only the acid, not the duodenogastric alkaline reflux, which is also very important in the genesis of the inflammatory esophageal lesions. The esophageal manometry, however, evaluates only the mechanical state of the lower esophageal sphincter and the peristaltic function of the esophageal body but does not provide any direct information about the exposure of the esophagus to the gastric juice. The aim of this study is to analyze the problems concerning the definition and the diagnosis of the gastroesophageal reflux disease with particular attention to the practical implications on the common surgical practice, and to review some solutions reported in the literature for the difficult clinical approach to the patient with this pathology.