Background: Our laboratory has carried out an epidemiological surveillance of Helicobacter pylori antimicrobial susceptibility since 1997. Aim: To report the antimicrobial susceptibility of H pylori strains, isolated in Chile from August 1997 to August 2000. Material and methods: Ninety one H pylori strains, obtained from antral gastric biopsies during upper gastrointestinal endoscopies were studied. Susceptibility towards clarithromycin, amoxicillin, bismuth subcitrate and metronidazole was studied by an agar diffusion technique. Results: All strains were susceptible to amoxicillin and two strains were resistant to clarithromycin. Forty two percent of strains were resistant to metronidazole and 13% were resistant to bismuth subcitrate. Conclusions: These results underscore the need to maintain an epidemiological surveillance of H pylori antimicrobial susceptibility, to modify its eradication therapy accordingly. (Rev Méd Chile 2000; 129; 643-6