Giardia intestinalis (G. intestinalis) and Helicobacter pylori (Hpylori) are two intestinal pathogens sharing the same mode of infection. This study determines the prevalence of G. intestinalis and H pylori co-infection estimated risks and predictive factors for susceptibility to co-infection. Stool samples were collected from 801 patients suffering gastrointestinal symptoms and living in Greater Cairo. They were subjected to coproscopic examination for detection of intestinal parasites and copro PCR-restriction fragment length polymorphism (PCR-RFLP) and sequencing targeting the glutamate dehydrogenase (gdh) gene for Giardia. Positive samples for gidrdiasis were further subjected to copro- immunoassay to detect H pylori coprontigen. Among 63 cases of giardiasis by both microscopy and PCR (84.1 % as-semblage B and 15.9% AII), 52.5% were coinfected with H pylori. Co-infection was more frequent with assemblage B (50.9%) than assemblage A (40%). Among studied variables of assemblage type, gender, or harboring more than one parasite (polyparasitism), only school age children, was signifi-cantly associated (P value: 0.02) with Giardia and H pylori co-infection. Physicians in Egypt must consider G. intestinalis and H pylori as prevailing intestinal pathogens with predominance of Giardia assemblage B. Giardia and H pylori co-infection is common in school aged children and modulates gastrointestinal manifestations. Intestinal parasitism and H pylori association is complex and necessitates further genomic studies for a better understanding of the epidemiological and clinical impact of co-infection, as well as possible strategies for their treatment and control.