Introduction: The SARS-CoV-2 virus is a new strain of the virus that caused the Covid-19 pandemic. The pandemic has greatly changed the everyday life in which we live, directing our behavior to prevent the spread of the infection itself. Children also have a big change in their everyday life. Reduced stay in collectives, fewer group activities, increased hygiene of hands and spaces where they stay, caused children to be less exposed to pathogens in the environment than before. Aim: The goal of this research is to compare the number of reported cases of infectious diseases specific to the child population in 2020 with reported cases in the period from 2010-2019. in Republic of Croatia. Methods: Total of 11 infectious diseases from the registers of infectious diseases in the Republic of Croatia in the period from 2010 to 2020 were analyzed, which was compared with the χ 2 for the year 2020. The SPSS program (version 26.0, SPSS Inc., Chicago, IL, USA) was used with a statistical significance of 5%. Results: Analyzing the data, the results show that the incidence of the infectious disease head lice decreased statistically significantly during 2020, while for children's infectious diseases caused by enteroviruses, enterocolitis, whooping cough, measles, itch and mumps, there is no statistically significant difference in the incidence in the observed periods, and for the diseases infectious mononucleosis, streptococcal sore throat, chicken pox and scarlet fever have statistically significantly increased their incidence in selected age groups. Conclusion: This research corroborates studies conducted outside the Republic of Croatia that compare applications and visits to doctors due to infectious diseases before and during the pandemic, and that there is a significant reduction in infection with certain pathogens characteristic of children's infectious diseases. The research reinforces the position that the surveillance system for infectious diseases should be strengthened even during pandemics, and vaccination coverage should be monitored in order to avoid further epidemics, as well as monitor the occurrence and trend of infectious diseases and incorporate existing knowledge in controlling them.