There is a paucity of data on the long-term behavior of dyspepsia, endoscopic findings, and gastroduodenal histology in patients with or without Helicobacter pylori colonization. We evaluated these parameters during a period of 7 to 19 years (average, 12.3 years) by baseline and follow-up studies. In 36 patients studied, the pattern of gastroduodenal dyspepsia and esophagogastroduodenoscopy findings remained essentially unchanged in 67% and 56% respectively. Dyspepsia patterns did not correlate significantly with either endoscopic or histologic findings, including the severity or location of gastritis in the fundus or antrum, or the presence or absence of H. pylori gastritis. Of 36 patients with adequate biopsies of the fundus and antrum, H. pylori colonization with gastritis was present in 73% but not in 27%. Progression to various degrees of atrophic gastritis was noted in 100% with, and in none without, H. pylori gastritis. In the fundus, atrophy progressed from 14% to 56%, but intestinal metaplasia did not change. In the antrum, atrophy increased from 22% to 64% and intestinal metaplasia increased from 17% to 36%. No patient demonstrated dysplasia, but severe atrophy was seen in the fundus (6%) and antrum (11%). Only two patients (5%) had severe loss of glandular elements and very low pepsinogen I, and thus can be considered to have developed advanced gastric atrophy.