Background: The mucosa distal to the endoscopic mucosal change zone can have easily diagnosed early alterations, in patients with chronic gastroesophageal reflux. Aim: To determine the type of mucosa existent in the zone distal to the squamous-columnar junction in patients with chronic gastroesophageal reflux without intestinal metaplasia. Patients and methods: One hundred thirty four controls and 208 patients with chronic gastroesophageal reflux lasting two years were studied. Forty three of these patients had a normal endoscopy, 54 had an erosive esophagitis and 111 had a short columnar epithelium covering the distal esophagus, without intestinal metaplasia. In all subjects, four biopsies were obtained from a zone distal to the squamous-columnar junction and two from the distal gastric antrum. Results: In 59% of control subjects, fundic mucosa was present in the zone distal to the squamous-columnar junction. Cardial mucosa was present in the rest. In patients with chronic gastroesophageal reflux, cardial mucosa was predominant. Helicobacter pylorii infection decreased along with increasing extension of cardial mucosa covering the distal esophagus. Conclusions: In patients with chronic gastroesophageal reflux there is a metaplasia of fundic mucosa towards cardial mucosa. On the other hand, Helicobacter pylorii infection decreases gradually.