Vaccination is one of the most effective preventative health measures in modern times. It has positively affected the incidence and prevalence of a myriad of diseases, as well as improved both their morbidity and mortality. It is essential that health care providers understand the value of this intervention, promote comprehensive immunization coverage within their community, and recognize the underlying principles that guide decisions regarding vaccination. Factors important to consider before immunization administration include the type of vaccination, its recommended timing and intervals, and the presence of contraindications, precautions, or other special considerations.