Children having leukemic usually suffer from many health problem as a result of the disease process. The purpose of the study was to assess knowledge and practices provided by mothers for the care of their children having leukemia. Research design:  A descriptive research design was utilized to conduct this study. Setting: The present study was conducted at out- patient clinic of pediatric oncology in the National Cancer Institute at Cairo University. Sample: A simple random sample was used to collect the total number of the sample was 366 mothers. One instrument was used; A) structured interviewing questionnaire it had four parts: 1. Demographic characteristic of the children, 2. Demographic characteristics of the mothers, 3. Exposure of the mothers to risk factors of leukemia, 4. Medical history of the disease as past and present history. B). Mothers' knowledge questionnaire sheet, C). Reported practices questionnaire sheet. Results: 64.2% of studied sample had poor knowledge, 83.3% had satisfactory total reported practices. Conclusion: An approximately two thirds of mothers (64.2%) had poor knowledge. Where more than three quarters of them had satisfactory practices (83.3%).Recommendation: Health education programs for mothers who having children with leukemia to prepare them with needed knowledge and skills. This study can be applied on a larger sample at other setting.