The cag7 gene of Korean H. pylori strains was analyzed by RFLP to develop a discriminatory tool for genotyping clinical isolates. For this study, a total of 82 H. pylori strains were isolated from the patients; 27 strains from the patients with chronic gastritis, 26 from duodenal ulcer, and 29 from gastric cancer. Genomic DNA was isolated and subjected to PCR targeting entire ORF or the repeat regions I and II of cag7 gene. PCR products from entire ORF or repeat region I of cag7 gene were divided into two types. However, there was no difference in the length of PCR products from the repeat region II. By the PCR genotyping of the entire cag7 gene, genotypes A and B were established, which showed approximately 5,100 and 5,500 bp PCR products, respectively. The repeat region I showed approximately 600 or 1,000 bp DNA fragments by PCR. The length of cag7 gene was determined by the size variation in the repeat region I. In addition, RFLP analysis of the PCR products of cag7 gene showed 11 subtypes, based on the major bands. These findings illustrate that the genetic diversity of the repeat region I would serve a reliable target for the genotyping of the cag 7 gene.