Abstract A child's ability to maintain a healthy diet and nutritional intake may be significantly influenced by receiving a cancer diagnosis and undergoing treatment. Inadequate oral intake can lead to a decline in nutritional status, which can affect organ and immune system function and require medical attention. A comprehensive dietary history is therefore necessary for a nutritional assessment. Aimed of the study was to evaluate the effect of nutritional education guidelines on parents' knowledge, reported practice and outcomes of children receiving chemotherapy. A quasi-experimental research design was conducted at pediatric Hematology and Oncology unit at Benha Specialized Pediatric Hospital affiliated to Ministry of Health. three tools used; First a Structured Interview Questionnaire form to collect data about characteristics of studied children's parents and their knowledge and Practice. The second tool was Reported Brazilian Healthy Eating Index-Revised (BHEI-R): dietary assessment. and Third Physical Assessment tool to evaluate the diet of the children under study. The results indicated statistically substantial improvements in the average score of parents' general knowledge and actions at the prior (r= .672**), post (r= .506**), and follow up (r= .576**) program phases, It can be concluded that The guidelines seem to have improved parents' knowledge and practice about nutrition for their children undergoing chemotherapy. Therefore, this study recommended that it is necessary to create and execute educational guidelines in pediatric oncology and hematology clinics in order to enhance parents' understanding and behavior with relation to feeding children with cancer.