Background/Aims: Antibiotic resistance in Helicobacter pylori varies according to geographical region. It is important to be informed about the local antibiotic resistance of H. pylori because treatment for H. pylori infection is often started on an empirical basis and, if the infecting strain is resistant, successful eradication is compromised. The aim of this study was to assess the prevalence of primary antibiotic resistance in H. pylori isolates from Korea. Methods: We studied the primary resistance rates among 652 H. pylori isolated from Korea in relation to collection date, disease presentation, age and gender. H. pylori were isolated from gastric mucosal biopsy specimens. Measurement of MICs for the recovered H. pylori strains was performed by the serial two-fold agar dilution method. Results: Resistance rates were 40.6%(metronidazole), 5.9%(clarithromycin), 0%(amoxycillin), 1.5%(furazolidone) and 1.5%(nitrofurantoin). Resistance to metronidazole and clarithromycin increased from 1994 to 1999(from 33.3 to 47.7% and 4.8 to 7.7%, respectively), but the differences only reached significance when rates of metronidazole resistance in women were compared with those in men(48.6 versus 36.9%). Conclusions: Further increases in antibiotic resistance and the development of dual and/or triple antibiotic resistance among H. pylori isolates from Korea would require susceptibility testing before treatment to maximize efficacy of H. pylori eradication therapies. (Korean J Helicobacter Res Prac 2002;2:57-60)