Background: Childhood vaccination has a great role in major worldwide reductions in morbidity and mortality and is considered to be one of the most effective public health interventions in terms of numbers of infections and deaths avoided per year. Objectives: To assess knowledge and practice regarding the new children's obligatory vaccination schedule (2018) and to identify barriers of incomplete vaccination and the sources of their information. Method: A cross-sectional study was conducted on 290 mothers. Through a multistage sampling technique, four health facilities were selected to represent Sharkia governorate whereas the sample units were proportionally allocated. The study included mothers of children younger than one year of age. Mothers were interviewed using the Fahmy questionnaire to assess the socioeconomic status and a modified semi-structured questionnaire to assess mothers’ knowledge and practice and to identify sources of their information and possible barriers of incomplete vaccinations. Results: The studied mothers showed an inadequate total knowledge score (61%) and poor total practice (59%). Mothers’ age, education, and occupation affected the total knowledge. Mothers’ education, occupation, and social class were the determinants affecting the total practice score. Health care providers (71%) and family relatives (67%) were the commonest sources of information. Sick baby (63%) and presence of family problems (31%) were the commonest barriers for none or incomplete immunization. Conclusion: The knowledge and practice of the studied mothers were unsatisfactory. Continuous health education should be provided to overcome the found barriers and encourage complete immunization.