- Background: Selective IgA deficiency (IgAD) is the most common primary immunodeficiency in the Western world. The aim of the study was to investigate the prevalence and clinical characteristics of Helicobacter pylori (H. pylori) infected dyspeptic patients with IgAD. Materials and methods: Case samples were drawn from all subjects ≥ 12 years of age (n = 104729), who that had undergone serum total IgA measurements during 2004 - 2014 years for any reason at Leumit Healthcare Services (Israel) and had serum total IgA <0.07 g/L. The control group was comprised of a random sample of remaining patients with a case-control ratio ten controls for each case. The dyspeptic diseases were identified and retrieved from Leumit Health Care Services electronic database using specific ICD-9-CM diagnostic codes. Results: Case group included 347 subjects and Control group 3470 subjects. There were no significant difference in the prevalence of patients with dyspepsia (84 (24.2%) vs 821 (23.6%) for cases and controls, respectively). Additionally, there was no difference in a proportion of dyspeptic H. pylori-positive subjects (59 (17.1%) vs 524 (15.1%) between the case and control groups.Only 59 (17%) among the 347 IgAD patients underwent gastroscopy. Crude numbers of all the patients with experienced gastritis. A significantly larger proportion of case subjects experienced several forms gastritis (13 (61.9%) vs.38 (21.6%), p<0.001), duodenal ulcers (7 (33.3%) vs 19 (10.8%); p = 0.01) and nodular lymphoid hyperplasia (NLH) (2 (9.5%) vs 0; p=0.011). Conclusions: IgAD is not associated with increased prevalence of H. pylori associated dyspepsia, nevertheless H.pylori infected dyspeptic IgAD subjects experience more EGD proved gastritis, duodenal ulcers and NLH. This article is protected by copyright. All rights reserved.