Background/aims: To determine H. pylori eradication rate with lansoprazole-amoxicillin-clarithromycin treatment regimen, which is the most frequently used as first-line therapy, in the Kırıkkale region. Methods: One hundred and five patients (44 male, 61 female) with H. pylori infection were included in the study. Patients were divided into two groups based on the endoscopic findings: non-ulcer dyspepsia (n=84, 31 male, 53 female) and acute gastric or duodenal ulcer (n=21, 13 male, 8 female) groups. The diagnosis of H. pylori infection was confirmed if both the urease test and histological examination, which were performed on endoscopic biopsies, were positive. Lansoprazole 30 mg, amoxicillin 1 g, and clarithromycin 500 mg were given twice daily for 14 days to all patients. Endoscopic biopsies were repeated for the evaluation of eradication three months after the treatment. Results: Ninety-six patients completed the study. Eradication rates were found to be 45.8% (44 of 96) in all patients, 42.1% (32 of 76 patients) in the non-ulcer dyspepsia group and 60% (12 of 20 patients) in the gastric or duodenal ulcer group for per protocol analysis, and the difference between non-ulcer dyspepsia and gastric or duodenal ulcer groups was not statistically significant (p=0.208). Conclusions: Lansoprazole- amoxicillin-clarithromycin treatment regimen, the most frequently preferred regimen in H. pylori eradication, is ineffective in our region. The low eradication rates observed with lansoprazole- amoxicillin-clarithromycin, at least in our region, bring into question its use as a first-line therapy. The use of alternative treatment protocols or antibiotic susceptibility test before the treatment may be helpful in achieving successful eradication with first-line therapy.