Infectious diseases are the most common occurrence among children of early and preschool age. Most of us have once in our lives suffered from an infectious disease listed and described in this paper. The source of infectious diseases is a pathogenic microorganism that is transmitted by certain routes and reaches the front door of the host, and the virulence or infectivity and number of microorganisms and the resistance or sensitivity of the host depends on whether an infection will occur. Meaningful and targeted action by us as individuals (educators and/or parents) on the previously described stages of infection formation can contribute to the prevention of infection. The aim of this paper is to present and familiarize with the causative agents, types and symptoms of infectious diseases, and each disease is separately presented and described through the clinical picture and course of the disease, diagnosis and treatment. It is crucial to educate educators and parents so that they can prevent the occurrence of infectious diseases, prevent the spread, but also recognize the symptoms if an infection occurs. Cooperation is needed at all levels, starting with the cooperation of the state and educational institutions, primary health care and kindergartens, the cooperation of parents and educators is always important. It is also important to educate the population and the population about the importance and benefits of vaccines against infectious diseases. Many underdeveloped countries still have a high mortality rate of early and preschool children due to infections caused by infectious diseases. Therefore, with today's modern and advanced medicine and science, it is a shame not to use the full potential available to us, all with the aim of improving and raising the standard of living.