By entering preschool, children increase their risk of contracting various diseases. Educators, as employees who are in the first and longest contact with children during their stay in groups, are an important predictor in assessing the child's condition. Recognition of risk factors and timely reaction of educators is essential in order to protect the health of children in the collective. The research was conducted in several preschool institutions in Trogir and the surrounding area, where with the help of a questionnaire, examined knowledge of educators about the most common diseases and their prevention in children. The aim of the research was to examine the knowledge of preschool educators about the most common diseases and their prevention in early and preschool children. The results of the research on educators' knowledge about children's diseases were worse, while educators knew much better about the prevention of the diseases themselves. The difference between educators with more or less than 20 years of experience was not significant, except in the question of vaccination. From the results of the research, we can conclude that educators who work in 10-hour programs will encounter sick children more often than educators who work in shorter programs, as well as that educators with more than 10 years of work experience will sooner admit children to the group that show signs of symptoms from educators with less than 10 years of work experience. Also, research has shown that educators under the age of 40 believe that it is more necessary to have more classes and practice on diseases and prevention in early and preschool children during their studies than educators over 40. Conclusion: Educators who work in preschool institutions need better quality education, starting at colleges with more theoretical and practical parts. It is necessary to educate teachers about diseases and their prevention throughout their working life.