Background : One‐week triple therapy has been suggested to be superior to two‐week omeprazole‐clarithromycin therapy for the cure of Helicobacter pylori infection. However, direct comparisons of the two treatments are scarce. Aim : To compare triple with dual therapy for H. pylori infection in the primary care setting. Methods : One hundred and forty‐five patients with duodenal ulcer and H. pylori infection were randomized to receive omeprazole 20 mg b.d. and clarithromycin 500 mg t.d.s. for 14 days (OC14 group, 69 patients) or omeprazole 20 mg b.d., clarithromycin 500 mg b.d. and amoxycillin 1 g b.d. for 7 days (OCA7 group, 76 patients). Eradication was evaluated by the 13C‐urea breath‐test. Results : Intention‐to‐treat analysis showed a cure rate of 48% (95% CI: 36–60%) in the OC14 group, and 71% (95% CI: 59–80%) in the OCA7 group (P=0.0004). Per protocol analysis showed cure rates of 51% (95% CI: 38–63%, 33/65 patients) and 82% (95% CI: 70–90%, 54/66 patients), respectively (P=0.0001). There were no significant differences in compliance or side‐effects. Conclusion : One‐week twice‐daily triple therapy is superior to 2‐week dual therapy, but the cure rate in primary care was far below 90%.