Background: The prevention and treatment of hypertension are a high priority in medicine Background: It has been recently reported by WHO that a large proportion of children fail to complete their immunization schedule. System weaknesses, low public awareness, fears and misconceptions about vaccines were responsible for that. Despite nearly 100% vaccination rate in Saudi Arabia, often parents delay vaccination and do not fully understand the value of immunization, except that it is mandatory for birth certification and admission in school. Objectives: To assess parental knowledge and attitude regarding vaccination and their effects on vaccination practice. Methodology: A cross-sectional study was conducted using a self-administered Arabic questionnaire, including 20 questions related to parental knowledge, attitude, and practice regarding childhood vaccination. It was distributed in PHC settings. Results: The study included parents of 390 children. Factors significantly associated with better knowledge score and positive parental attitude regarding child vaccination were source of information about child vaccination from TV, internet and journals/newspapers, parents with first child, younger age, and higher level of education. There was a moderate positive correlation between total knowledge score and total attitude score of child vaccination (r=0.382, p<0.001). Conclusion: Positive attitude towards immunizations was remarkably high in this study group of parents. Knowledge on childhood immunizations, however, was not significantly higher in those who reportedly receive information from health professionals.