AIM: The most accepted treatment for infection by Helicobacter pylori is the proton pump inhibitor based therapy with two antibiotics. However, there is no consensus regarding the duration. The purpose here was to compare eradication percentages in the omeprazole+amoxicillin+clarithromycin regimen administered during 7 days versus 10 days and confront the results with a previous 14-day* experience in Peru. METHOD: Patients from the Central Military Hospital and Peruvian-Japanese Hospital evidencing chronic upper gastrointestinal tract symptoms were recruited. We excluded patients with peptic ulcer. Biopsies were taken for diagnosis, for urease and PCR tests, culture and coloring with silver. Omeprazole+clarithromycin+amoxicillin was used during 7 days versus 10 days. Control endoscopy was performed one month after treatment had been completed and molecular biology techniques were used to differentiate recurrences from new infections. Susceptibility to clarithromycin was assessed. RESULTS: 36 patients were included in each group. Eradication was the same in both groups: 86.1% (31/36). In several patients in whom the bacteria persisted, the same initial nucleus was found. In a previous study* using this same regimen during 14 days, a 93% eradication was obtained. 91.18% of our samples were susceptible to clarithromycin. CONCLUSIONS: In Peru, the omeprazole+clarithromycin+amoxicillin combination gives results higher than 80% in the eradication of infection by Helicobacter pylori. The 7 and 10 days regimens eradicated the bacteria in 86% of our patients.