Gastroesophageal reflux disease (GERD) is one of the most common gastrointestinal diseases in the world. This article gives an overview about diagnostic procedures for GERD. Standard procedures such as pH-metry, Bilitec and manometry and also new diagnostic tools such as combined multichannel intraluminal impedance (MII) and pH-metry and Bravo Capsule are described in detail. Established endoscopy criteria as well as innovative techniques such as magnification, narrow band imaging and computed virtual chromoendoscopy are also presented. Not all of these procedures need to be used in every patient. Therefore, it is important to know the technical aspects, indications, advantages and disadvantages of each method in order to appropriately use any of these tests. The final goal is to characterise GERD and provide the patient with an appropriate therapy.