The aim of this study was to examine the frequency and the relationship of H. pylori infection and giardiasis in children with recurrent abdominal pain. The study group included 98 patients and 88 healthy controls. Patients' sera were examined for anti-H. pylori specific IgG antibodies using H. pylori IgG ELISA. Analysis of stool samples was carried out by the H. pylori stool antigen (HpSA) enzyme immunoassay. For the diagnosis of giardiasis, all stool samples were examined by saline-Lugol and formalin-ethyl-acetate sedimentation methods. H. pylori was detected in 40 (49.0%) patients and 40 (45.5%) controls. G. intestinalis was detected in 30 (30.6%) patients and 18 (20.4%) controls. There was no significant difference in frequency between the groups in the distribution of H. pylori (p=0.6) and giardiasis (p=0.4). The frequency of the combination of H. pylori infection and giardiasis in the patient groups was 22.4% compared to 6.8% in the control groups and this result was statistically significant (p=0.002). It seems that the relationship of H. pylori infection and giardiasis represent an important ethiologic factor in children with recurrent abdominal pain.