
A Case-control study was carried out to determine the frequency of Helicobacter Pylori (H. pylori) infection by H. pylori stool Ag test in malnourished children and it's relation to some selected variables. Sixty seven malnourished infants and children who have been admitted to nutritional rehabilitation center (NRC) in Basra General Hospital were regarded as cases and one hundred thirty nine healthy children who have visited primary health center, were regarded as control, their age ranged from 2 – 36 months over the period from the first of February till the end of September 2012. A special questionnaire was designed for the purpose of the study, information included: age, sex, presenting symptoms, past history, feeding history, and history of treatment with antibiotics. Measurements of weight and length by standard procedure done for all infants and children recruited in the study. Anthropometric data (weight and length) are applied to appropriate charts according to CDC/WHO charts. The study revealed a significantly higher percentage of positive H. pylori stool Ag in malnourished patients than control group (35.8%, 10.8%) respectively, p < 0.0001. In addition higher frequency of positive H. pylori stool Ag was found in patients with severe malnutrition than moderate malnutrition (54.2%, 45.8%) respectively but statistically not significant result p > 0.05. Regarding the sex of studied children although females have higher percentage of positive H. pylori stool Ag in both malnourished and healthy children (66.7%, 60%) respectively, but the difference statistically in not significant p>0.05. Positive H. pylori stool were found in higher frequency in malnourished patients older than 12 months (54.2%) compared to infants (45.8%) but in the control group there is a higher frequency of positive H. pylori stool in infants younger than 12 months (60%) compare to children older than 12 months (40%) and statistically not significant p > 0.05. Malnourished and control group who were not breast fed have higher frequency of positive H. pylori stool (70.8%, 73.3%) respectively than those with history of breast feeding (29.2%, 26.7%) respectively and statistically not significant p > 0.05. But absence of breast feeding is significantly associated with H. pylori infection in malnourished patients and control p < 0.05. Gastrointestinal symptoms were common presenting symptoms in malnourished patients 67.2%, with significant association with positive H. pylori stool Ag p > 0.05.as well as more than (56%) of malnourished patients with history of recurrent diarrhea have positive H. pylori stool Ag. Diarrhea is significantly associated with H. pylori infection in malnourished children. So detection of H. pylori infection by simple H. pylori stool Ag test allows early diagnosis and treatment to counteract its effect on growth of infants and children.