Introduction: A variety of PCR methods have been widely used to detect Helicobacter pylori in clinical specimens. It is necessary to evaluate the most sensitive and specific one. Aim: To evaluate the 5 PCR methods for the detection of H pylori in the same individual gastric biopsy specimens. Method: We have examined 20 CLO test positive and 50 CLO test negative gastric biopsy specimens for H. pylori by five different PCR methods, including the adhesin gene PCR, species-specific antigen PCR, 16s rRNA gene PCR, urease A gene PCR, and urease C gene PCR. The beta-actin gene PCR was performed as internal control, and all specimens tested were positive by this PCR. Results: All 20 CLO test positive specimens were positive by all PCR methods except the urease A gene PCR, which produced positive results only in 2 specimens. Among the 50 CLO test negative specimens, 15 specimens were positive by the adhesin gene PCR, 9 by the species-specific antigen PCR, 2 by the urease C gene PCR, 0 by the urease A gene PCR, and all 50 by the 16s rRNA gene PCR. Conclusions: These results indicate that the urease A gene does not have sufficient sensitivity for the detection of H. pylori and that 16s rRNA gene PCR is not specific to H. pylori. All the other 3 methods (the adhesin gene PCR, species-specific antigen PCR, and urease C gene PCR) appear to have sufficient sensitivity to detect H. pylori. The results of this study also suggest that the urease C PCR is most specific to H. pylori.