The knowledge of the mothers on immunization - a public health intervention that has greatly reduced mortality and morbidity globally- is very vital as they play a great role in child care. Their ability to have the right knowledge will enhance their practice and attitude toward immunization. This cross- sectional descriptive study was conducted in Khartoum State Ummbada locality (Albugaa) in period from 5th February to 6th March-2017. Aimed to study the knowledge, attitudes and practice of mothers with children under five years toward vaccination, the study was included 384 mother which have children under five years, divided into six area. The data was collected through questionnaire and interview, and data was analyzed by handily an excel program. The study shown that the majority 90% of mothers heard about the hear of vaccination, about 52% of mothers had poor knowledge about number of the routine doses which given to the child less than two years, 55% of mother had negative attitudes toward vaccination of child in vaccination campaigns, and 66% of mothers good practice toward their treated with the side effects of vaccines. We recommended to Ministry of Health of Khartoum State should be conducting health education campaigns about vaccination for mothers continuously through media and Provided mothers with vaccination booklets explain the importance of vaccination, routine doses, importance of vaccination card and how to manage the sideeffects of vaccination, and obligating all health centers to provided health instructions about vaccination for mothers.