Gastroscopy is the preferred method of diagnosis of upper gastrointestinal (UGI) disorders which often present with dyspepsia. Since the discovery of helicobacter pylori (H. pylori) as an important aetiological agent in gastroduodenal disease, investigation for this organism during UGI endoscopy has become a standard clinical practice. We have studied a large number of Nigerian patients with dyspeptic symptoms referred for endoscopy for the spectrum of gastroduodenal diseases and the incidence of H. pylori infection. Detection of H. pylori was done on gastric muscosal biopsies either by the Campylobacter-Like Organism (CLO)-urease test or by histropathology. A total of 834 patients were studied out of which 268 were investigated for H. pylori. A hundred and ninety-five patients (73%) were positive for H. pylori and the peak age was in the fourth decade. Duodenal ulcer (DU) was the most common endoscopic finding (38.7%). The incidence of H. pylori infection was 76% among patients with DU, gastritis, gastroduodenitis and gastric outlet obstruction. However, all the anterior and pyloric channel Duus tested for H. pylori were positive gastric ulcer (GU) was diagnosed in only 4.7% of patients but 82% of them tested for H. pylori were positive. H. pylori was significantly associated with GU occurring with gastritis. Gastric carcinoma was diagnosed in 52 patients (6.2%) and 50% of those tested for H. pylori were positive. This study shows that H. pylori plays an important role in the aetiopathogenesis of peptic ulcer disease among Nigerian patients and that the diagnosis of anterior and pyloric channel Duus or gastroesophageal polyp disease may be an indicator of massive H. pylori infection.