Vaccination is entering antigens interionally in a persons organism in order to induce creating antibodies. Taking active and passive immunation prevents the occurence of infections diseases. Vaccination in children age has a great significane since infetcions diseases are dangerous for children. In the Republic of Croatia exists a Schedule of mantatory immunation for children and it includes mandatory vaccation against tuberculosis, hepatitis B, diphtheria, tetanus, pertussis, haemophylusa influenzae, measles, mumps, rebeola and poliomyelitis while rabies, yellow fever and abdominal typhus are vaccinated according to indications. It is necessary to respect the interval od thirty days betwen two different live vaccine which aren't given at the same time. Every vaccation has contraindications for vaccine, so they are divided on general and sprecific. After being vaccainated whitin four weeks side effects may occur. Although today's vaccines are highly effective, not one is entirely harmless and therefore monitoring unwanted side effects is a great significance. The percentage of side effects which are related to the appliance of vaccine is heligible due to the risk of complications and death outcome from the diseases from it is being vaccinated. Side effects can be divided on local and general. In comparison od side effects from the year od 2010 and 2015 a significant drop is visible. In 2010 the most seposted side effects had the MO -PA – RU vaccine while 2015. the higest number od seposted side effects was vaccinated against dipheria, tetanus, whoaping cough, infatile paralysis and Haemophilus influenzae type B. Although the systemic and mandatory immuunization in Croatia lead to succeding in suppression oft he disease, it must continue to apply in order to keep and achieve better results, whit the big help from nurses.