Parasitic infections might become life threatening in immuno-compromised children' The study assessed the parasites' prevalence in different groups of immuno-compromised children. It was conducted on 120 children of whom 90 were inpatients in Tanta University Pediatric Hospital and were divided into 6 groups. GI: malignant diseases, GII: renal diseases, GIII: aggressive corticosteroid therapy, GIV: malnourished, GV: diabetic & GVI: miscellaneous. GVII comprised healthy children as control. Each child was subjected to history taking, clinical examination and examination of 3 stool samples by direct wet smear and a concentration technique. Coproculture and smear staining by a special stain, as well as examination of one blood sample for anti-Toxoplasma antibodies were done. The diagnostic efficacy of an immuno-chromatographic test for Giardia/ Cryptosporidium coproantigen was also assessed. The results revealed parasitic infections in 62.2% of the children in the test groups. Cryptosporidium was the most prevalent (33.3%). Cryptosporidium and Microsporidia were significantly prevalent in GI, Giardia was significantly high in GII, and Strongyloides stercoralis was detected in GIII. Coproantigen detection test showed 100% sensitivity, 87.5% specificity and 95% accuracy for Giardia; and 13.3%, 100%, 35% for Cryptosporidium respectively.