BackgroundHelicobacter pylori is the main etiology of peptic ulcers and chronic gastritis. Various studies showed that blood type ‘O’ is more common among patients with peptic ulcer. The aim of this study was to determine the seroprevalence of H. pylori antibodies and its relationship with ABO/Rhesus blood groups, age, sex and residence of symptomatic patients in southern Ethiopia.MethodsA cross-sectional study was conducted in a total of 408 consecutive patients with upper abdominal complaints at Hawassa University Hospital from October 2012 to January 2013. Data on demographic factors was collected from all participants using questionnaires. Blood samples were also collected and tested for ABO and Rh blood group phenotype using hemagglutination test and for anti-H. pylori antibody (IgG) using two different ELISAs..ResultsThe overall seroprevalence of H. pylori infection was 83.3% (340/408), and it was significantly higher in rural (71.2%) compared to urban residents (28.8%) (p = 0.008). Participants with blood group AB, A, O, B, and Rh positive had H. pylori prevalence of 88.9, 84.2, 83.7, 80.9, and 83.5%, respectively. H. pylori infection was not significantly influenced by age, sex, occupation, educational status and ABO/ Rh status (p >0.05).ConclusionThe high seroprevalence of H. pylori infection especially among rural residents calls for immediate intervention measures so that its clinical consequences could be minimized. ABO/Rh blood group was not found to be associated with H. pylori infection.