Parasitic infections are recognized as a major public health problem. In this study, 117 children having acute lymphocytic leukemia, 117 immunocompetent children to represent the control group and 24 children terminated their chemotherapeutic course for ALL and were free from illness were investigated aiming to study the Association of ALL in children with some ecto and endo- parasites. Laboratory investigations including the analysis of stool, urine, cerebrospinal fluid and blood samples. We concluded that the percentages of infection among leukemic children were higher than the immunocompetent children. Parasitic infection were (90.6%) & 58.1% among leukemic children & controls respectively. Protozoa recorded 66.7% & 44.4% among the leukemic children & controls respectively. Followed by microsporidial infection (60.7% vs. 11.1%), then by coccidial infection (53.8% vs. 41.9%), Toxoplasma gondii (13.3% vs.6%) & helminthic infection (2.6% vs. 12%). The percentages of Microsporidia infections in the CSF were 54.7% and 53.7% by using Quick-Hot Gram-Chromotrope & Giemsa respectively. The results showed no Toxoplasma gondii by Giemsa stain, also no Acanthameba was detected in th CSF.