The aim of the present study was to culture Helicobacter pylori under aerobic conditions and to investigate the characteristics of the organism when cultured aerobically. Most (22 of 23) of the Helicobacter pylori isolates grew under aerobic conditions, but with reduced viable cell counts. Blood agar was more suitable than chocolate agar. The morphological and enzymatic characteristics as well as the protein profiles of each organism were identical under aerobic and microaerophilic conditions. However, haemolysis of Helicobacter pylori was delayed under aerobic conditions. The MIC of metronidazole was slightly lower for some strains under aerobic conditions. These findings indicate that Helicobacter pylori is not only a microaerophilic organism but also adapts to aerobic conditions, which may have some important implications in microbiological and epidemiological studies.