As the incidence of both gastric cancer and peptic ulcer disease have declined, that of gastro-oesophageal reflux disease (GORD) and non-ulcer, or functional dyspepsia (FD) have reached virtually epidemic proportions. As we come to appreciate the expression of these disorders in the community, the real spectrum of each disease has become evident. FD and non-erosive reflux disease (NERD), the most prevalent manifestation of GORD, frequently overlap. Where then does GORD end and FD begin? Is it realistic, or even clinically relevant, to attempt a clear separation between these entities? These are more than issues of mere semantics; therapeutic options may be dictated by the classification of the patient as one or the other. Recent work indicates clearly that NERD is a heterogeneous disorder incorporating some patients who may well harbour subtle manifestations of oesophagitis and others who have entirely normal 24-hour pH studies. These differences may be crucial to the concept of NERD/FD overlap. While evidence in support of this concept is far from complete, it would appear that this overlap is most relevant to those NERD patients who do not exhibit abnormal esophageal acid exposure. These patients truly belong in the spectrum of functional gastrointestinal disorders rather than in GORD; attempts to shoe-horn these individuals into the spectrum of GORD will result in therapeutic disappointment and surgical disaster.