There is epidemiological evidence of an association between cigarette smoking and gastritis. To find out whether the reason for this might be related to the presence of Helicobacter pylori, biopsies were taken from the gastric corpus and antrum and from the duodenal bulb in 106 consecutive patients referred for oesophagogastroduodenoscopy because of epigastric pain. Patients with ulcer disease or cancer were excluded. The biopsy specimens were cultured for H. pylori and examined histologically for the presence and grade of gastritis and duodenitis. Thirty-five percent of the patients were H. pylori-positive and 57% had histological gastritis; 37% were cigarette smokers and among these, H. pylori was found significantly less frequently than in non-smokers (18 and 45%, respectively; 2p = 0.0083). Among patients colonized with H. pylori, gastritis was found in 89% compared to 39% in non-colonized patients (2p < 0.0001). In spite of this, 51 % of the smokers and 60% of the non-smokers (2p = 0.85) had histological gastritic mucosa. No differences in the severity of the gastritis or the duodenitis in patients with histologically positive findings could be seen when comparing smokers to non-smokers and H. pylori-positive to H. pylori-negative patients.