A total of one thousand and fifty (1050) young children from Mansoura Pediatric Hospital, July 2005 to July 2006 were examined for cryptosporidiosis. Detailed history was taken from each participant, stool examination by direct smear, Formalin-ether sedimentation, Sheather's floatation, modified Ziehl-Nel-seen (MZN) stain, Cryptospordium oocysts count, coproantigen detection by ELISA. Other infections were excluded. Out of 1050 children examined, cryptosporidial oocysts were detected in 90 cases by modified Zeihl Nelseen (MZN) stain, and copro-antigen ELISA added another 10 cases. There was a significant difference between age group (1-2 years), rural locality, nutrition status, and diarrhea regarding Cryptosporidium infection. There was highly significant difference in malnourished children regarding Cryptosporidium oocysts and ELISA-OD. There is a significant positive correlation between oocysts count, ELISA-OD and malnutrition. Only diarrhea had a highly significant difference in relation to other symptoms in both mean oocysts count and ELISA-OD. There was highly significant positive correlation between symptoms, oocysts count and ELISA-OD.