This study sought to determine the correlation between the emergence of internalized and externalized behaviour problems in preschool children with experienced stressful events and the assessment of their intensity of impact on children according to their parents' assessment. Stress and stressful events can have significant consequences on the general health, especially psychological, of both adults and children, but considering that children of preschool age do not yet have developed mechanisms for dealing with stress, it is very important to notice such events in children and their possible negative consequences in order to future benefits of children's physical, mental and emotional health. 307 participants, parents of early and preschool children from the Brod-Posavina County, took part in the research, who filled out the Child Strengths and Difficulties Questionnaire (SDQ questionnaire) and the Stressful Events Scale for Children (Stress-D) using an online questionnaire. assessments for their preschool child. The research showed a low presence of externalized and internalized behaviour problems in preschool children. Among the most common stressful events for preschool children are quarrels with parents, physical injury and discovery of some wrongdoing, and parents estimate that the most disturbing for their children was an encounter with death (brother or sister, grandparent or death of a parent and suicide), then the experience of illness of either a child or a close person and the accusation that the child did something that he did not. Children included in this research, according to their parents' assessment, showed little internalized and externalized behaviour problems, and they showed more externalized behaviour problems compared to internalized ones. Investigating the connection between internalized and externalized problems and the number of stressful events and their intensity, a low but significant positive connection of these behavioural problems with stressful events in children's lives and parental assessments of the intensity of their children's distress during stressful events was found.