The transition to kindergarten is a part of family life cycle and an expected developmental change that can induce stress and as such requires family adjustment. In this paper we deal with the types and sources of parental stress when a child enters the kindergarten and during the period of his/her adaptation. In the first phase of the study we conducted three focus group discussions, in which 20 parents participated. The second phase was designed for the questionnaire survey, in which the sample consisted of 163 parents. The data suggest that in parents’ experience the most frequent are stressful events related to the child’s reactions and changes in the child’s acquired habits. With less frequency parents reported about stress related to their own emotional reactions and changes in the family functioning. When compared, no significant differences were found between the fathers and mothers in terms of the frequency of the reported stress. Generally, parents estimate that stressful experience associated with children’s adaptation to kindergarten does not induce highly intense stress. Additionally, we found that mothers perceive the children’s period of adaptation to kindergarten significantly more stressful than fathers. Research findings can be important for future investigations about the effects of parental stress in the period of children’s adaptation to kindergarten on optimal family functioning, and for the practical implications for working with these families. [Projekat Ministarstva nauke Republike Srbije: Efekti egzistencijalne nesigurnosti na pojedinca i porodicu u Srbiji]