A urine-based enzyme-linked immunosorbent assay kit (URINELISA) for detection of the antibody for H. pylori has recently been developed. We evaluated the diagnostic capability of the URINELISA test in comparison with two serum IgG antibody kits (HM-CAP and Helico G) for H. pylori infection. The subjects of this study were 173 patients. H. pylori was detected by means of culture, immunohistochemical staining and rapid urease test of endoscopically obtained biopsy specimens. A positive diagnosis of H. pylori was when at least one of three tests was positive and a negative diagnosis when all three were diagnosed as H. pylori positive and 23 as negative. We also examined the diagnostic potential of the antibodies in urine and in serum by using the results of the bioptic methods as the gold standard. The sensitivity of both URINELISA and HM-CAP was 93.3% and that of Helico G 94.7%, while their respective specificities were 47.8%, 65.2% and 52.2%. The URINELISA kit thus showed high sensitivity but relatively low specificity. The latter was due to sampling errors in the bioptic procedure because the subjects of this study included many elderly patients with atrophic gastritis. The level of the antibody in urine decreased markedly after 2 months of eradication therapy. We conclude that the URINELISA kit is as effective as serum antibody kits for the diagnosis of H. pylori infection.