Contagious diseases such as plague, cholera and tuberculosis have taken a large number of lives in the past. Thanks to improvement of medicine, improved hygiene conditions and systematic vaccination, today’s condition is much better. Contagious or infectious diseases are the result of harmful microorganisms, usually viruses and bacteria entering the body. They have specific symptoms on which we can set a diagnosis and determine a treatment. Flu, cold and intestinal infections are contagious diseases that are very common among young school children. They are spreading very fast due to the easy way of transmitting, with sneezing or coughing drops and dirty hands. For a lot of contagious diseases such as mumps, rubella and measles there are vaccines. Due to a necessary vaccination they are much rare today. Apart from vaccination, there are other ways of preventing contagious diseases, such as hand hygiene, food hygiene, proper nutrition and physical activity. The main goal of this research was to question which preventive measures are taken by young school children in order to prevent the onset of contagious diseases and what do they do when they have one of these diseases. The research was conducted during the March 2017 by the survey method. 82 pupils of Primary School “Ivan Mažuranić” in Sibinj participated in the research. The given results have shown that students know and undertake many protective measures that can help them to prevent the most common contagious diseases.