OBJECTIVE The finding that some Helicobacter pylori strains express Lewis b (Le(b)) blood group antigen casts a doubt on the role of Le(b) of human gastric epithelium being a receptor for H. pylori. The aim of this study was to determine if expression of Le(b) in H. pylori interferes with bacterial adhesion property. METHODS Bacterial adhesion to immobilized Le(b) on microtitre plate was performed in 63 H. pylori strains obtained from Singapore using in vitro adherence assay. Expression of Lewis blood group antigens was determined by ELISA assay. RESULTS Among 63 H. pylori strains, 28 expressed Le(b) antigen. In vitro adhesion assay showed that 78.6 % (22/28) of Le(b)-positive and 74.3 % (26/35) of Le(b)-negative H. pylori isolates were positive for adhesion to immobilized Le(b) coated on microtitre plate (P=0.772). In addition, blocking of H. pylori Le(b) by prior incubation with anti-Le(b) monoclonal antibody did not alter the binding of the bacteria to solid-phase coated Le(b). CONCLUSIONS The present study suggests that expression of Le(b) in H. pylori does not interfere with the bacterial adhesion property. This result supports the notion that Le(b) present on human gastric epithelial cells is capable of being a receptor for H. pylori.