Background/objectives: Acute lymphocytic leukemia (ALL) is a worldwide problem, and it is more prevalent in children. As the chemotherapy is taken, the host defenses are altered and the patient becomes more liable to infection. This study aimed at determining the frequency of parasitic infections among children with ALL in relation to controls, and to evaluate the different techniques used in the diagnosis of these infections. Methods: The study was carried out in Alexandria University Children's Hospital at El-Shatby during one year. The study included 117 children with ALL, and same number of immunocompetent children as a control group. Stool, urine, cerebrospinal fluid (CSF), and blood samples were collected and prepared to be examined by different techniques. Results: The overall percentages of parasitic infections were 90.6% and 58.1% among leukemic children and controls, respectively. Microsporidiosis was the most prevalent infection, and Cryptosporidium parvum was the most common coccidial infection. Microsporidium was the only parasite detected in the CSF of leukemic children. The best technique was modified Ziehl Neelsen to detect coccidia, Trichrome stain for protozoa and Quick-Hot Gram-chromotrope stain for microsporidial infection. Conclusions: There was a high percentage of parasitic infections among leukemic children, and the results indicate that the combination of many techniques is more likely to be effective in the diagnosis of these infections.