The paper was prepared by an expert group appointed by the Polish Society of Gastroenterology with an aim to update and systematize the knowledge about diagnosis and treatment of gastroesophageal reflux disease (GERD). Based on the previously published guidelines of international societies, expert consensuses, and recently published good quality data, we formulated 74 statements regarding the definition, diagnosis and treatment of GERD and assessed the level of acceptance of these statements and the reliability of the data. We discussed in details the possibilities and limitations of the available diagnostic methods and therapies, with particular emphasis on the diversity of gastroesophageal reflux symptoms and complications including Barrett's esophagus. Practical principles regarding interpretation of the diagnostic tests are presented. In addition, we discussed the indications for surgical treatment as well as the situations in which surgical treatment is not indicated with emphasis on the importance of preoperative diagnostics. The role of add-on therapy and indications for maintenance treatment are defined.