Nonerosive reflux disease (NERD), now recognized as the most common manifestation of gastroesophageal reflux disease (GERD), typically features a similar range of symptoms to esophagitis and has an impact on quality of life which is at least as significant as that for erosive disease. The fact that not all patients with NERD exhibit abnormal acid exposure and that NERD, in general, frequently overlaps with functional dyspepsia may partially explain the observation that the response to proton pump inhibitors (PPIs) may be less impressive in NERD than among patients with erosive or even complicated disease. Furthermore, on the whole, NERD patients do not appear to have a good outcome following surgery. NERD is a multifactorial disorder and can be divided into three groups: patients who exhibit abnormal acid exposure; those who are acid sensitive; and those with functional heartburn. These subgroups may respond differently to PPIs and surgery and therefore need to be differentiated.