Giardiasis is one of the most common enteroprotozoal diseases; its association with Helicobacter pylori is a common clinical finding. This work studied the impact of such association. Fifty giardiasis patients were classified into two groups according to the concomitant presence of H. pylori and ten normal healthy controls were also included. All patients were subjected to complete history taking, thorough clinical and stool examination, endoscopy, and biopsy of gastric and duodenal mucosa as well as histopatological examination. Results revealed significant upper gastrointestinal symptoms (epigastric pain and anorexia) in giardiasis patients with H. pylori. Also, endoscopic and histopathologic examination showed significant gastric lesions in this group of patients as compared to those suffering only G. lamblia.