This study highlighted the prevalence of parasitic infection in type-1 diabetes mellitus children and evaluated the effect of intestinal parasites on fecal calprotectin as a part of innate mucosal immunity. A total of 431 children with gastrointestinal manifestations attended the outpatients clinics, Aboul-Reesh Pediatric Teaching Hospital, Cairo University were randomly selected. Medical sheets were filled out on each patient. Stool samples were collected in labeled covered cartoon boxes and macroscopically examined for adult worms and segments, and microscopically for ova and protozoa by Lugol's iodine1% smears and formol-ether concentration method, also, MZN was used for Cryptosporidium oocysts. Besides, stool samples were examined for Helicobacter pylori. The results showed that 171/431 (39.67%) were type-1DM (p=0.000) and 260 (60.32%) were nondiabetic used as positive control. The overall intestinal parasitosis was (45.26%), H. pylori was (39.47%), irritable bowel syndrome was (25.78%), inflammatory bowel disease was (3.96%). Treatment
of the causative agents diminished the gastrointestinal troubles.