It is well known that diabetes mellitus affects the immune system negatively through various ways. Diabetic patients are also considered as the immunocompromised group of patients. Infections with intestinal parasites are uncommon to cause high morbidity or mortality to man, but they are risky to diabetic patients. The study investigated the prevalence of common intestinal parasites in diabetic patients in Tanta City. Among the patients who were attending gastrointestinal department (360 patients), complaining of variouse abdominal symptoms and discomfort, thirty three (33) patients were known to be diabetic and on current treatment. Fecal samples were collected from diabetic patients and the same number from non-diabetic patients. Samples were examined macroscopically and microscopically by direct smear and different concentration methods then stained with iodine. The study was carried out through six months from March to August 2015 for common intestinal parasites. In diabetic group E histolytica were detected in 13 patients (39.4%), compared
to (43%) among controls, G. lamblia was detected in a patient (3%) compared to (3%) in controls, A. lumbricoides was detected in one patient (3%) compared to (5%) in controls, and E. vermicularis was detected in one patient (3%) compared to (3.8%) in controls. The highest level of parasitosis among diabetic patients was E. histolytica (39%), but without significant difference between controls and patients. There for one can assume that E. histolytica could be considered as a monitor for environmental pollution, low stander hygiene and low standard of living.