Immunization is a process of protecting an individual from a disease through introduction of live or killed or attenuated organism in the individual system. Immunization against vaccine preventable diseases is essential to reduce morbidity, mortality and handicapped conditions in children. Immunizing agents are vaccines, immunoglobulins, and antisera or antitoxins. Immunization schedule is planned according to the existing community health problems. National immunization schedule includes immunizations of children and pregnant women. As per schedule, for children, BCG vaccine is given to protect from tuberculosis, OPV is given to protect from poliomyelitis, DPT vaccine is given to protect from diphtheria pertussis and tetanus, HBV is given to protect from hepatitis –B, and measles vaccine is given to protect from measles. Tetanus toxoid is given to the pregnant women to protect both mother and baby from tetanus. Other available vaccines for children are against typhoid, mumps, rubella, haemophilus influenzae, rotavirus, Japanese encephalitis, cholera, etc. Cold chain equipments and their maintenance are essential part for successful immunization program. Nursing personnel are mostly responsible for administration of immunizations, maintenance of cold chain, record keeping, and health teaching to increase awareness.