Cigarette smoking is believed to be one of the major factors influencing duodenal ulcer (DU) recurrence. However, the influence of cigarette smoking on DU recurrence after the eradication of Helicobacter pylori has not been separately addressed. The aim of this study was to investigate DU relapse rate in smokers and nonsmokers, both with confirmed eradication of H. pylori. Patients with H. pylori eradication, demonstrated at endoscopy 4 wk post-treatment, were included in the study. Smoking history was obtained with a standard questionnaire, and patients were followed endoscopically, both yearly and at symptomatic recurrence, to detect anatomical DU recurrence. Of the 197 (121M:76F) patients enrolled in the study and followed for 1-6 yr, 80 (41%) were smokers, smoking 5-40 cigarettes/day. The 117 (59%) nonsmokers included 31 (26%) patients who had ceased smoking 4-20 yr ago. Another seven (9%) smokers ceased smoking during the follow-up period. In the 197 patients with eradicated H. pylori and cured DU, there has been no recurrence of ulcer, regardless of smoking status. We conclude that in patients with DU in whom H. pylori infection is eradicated, ulcer disease does not recur, as observed for up to 6 yr. Furthermore, cigarette smoking is not a risk factor for DU recurrence, provided H. pylori is eradicated.