Introduction: Routine immunization contributes immensely to decline the incidence of vaccine preventable diseases among children. Statistical data shown the sharply decrease the vaccination coverage rates in Sumy region of Ukraine. The aim: Assess routine immunization uptake and its effect on the incidence of vaccine preventable diseases among children in Sumy region of Ukraine. Review: During some years, only 50-60 % of Sumy region children had received all recommended vaccines, which is far below World Health Organization target of 80 %. This has led to an increase of morbidity associated with some infectious diseases. Outbreaks of measles were registered in 2006 and 2012, when were ill 9346 and 7931 children respectively. Massive measles outbreak ongoing nowadays. Total number infected have already exceeded 35,000 cases. Conclusions: RI uptake in Ukraine is still below World Health Organization target. The main reason for the ongoing measles outbreak was low vaccination coverage for routine immunization antigens as a result of which collective immunity decreased to a critical level. Strict monitoring of the implementation of the immunization schedule by medical institutions at all levels are recommended to improve vaccination status of Ukrainian children.