The present paper reviews the present state of gastro-oesophageal reflux disease (GERD), a clinical entity of great prevalence in the western population. We examine the progress made in the understanding of the pathogeny of this disease, determined to a large degree by the introduction of functional explorations, such as esophagic manometry and 24 hour pH-manometry, which have contributed information of great physiopathological interest. We describe typical and atypical or extra esophageal clinical manifestations, while bringing up to date the diagnostic methodology. Finally, we review the present state of treatment in its pharmacological, endoscopic and surgical facets