[Show abstract][Hide abstract] ABSTRACT: The beginning of school life is a special moment in the life cycle that may be influenced by stressful events such as family loss and separation, as well as by conflicting relationship patterns between the present family and the family of origin. This article aims to demonstrate the use of the genogram as a research instrument in developmental psychology with the following objectives: characterize the family configurations, identify stressful events in the families' life cycle, especially, loss and separation experiences, and to analyze the relationship patterns between the nuclear family and the family of origin. A collective case study was carried out with six families and their children age five to six, three of whom were considered as having an easy adaptation to school and the other three as having a difficult adaptation. The mothers were interviewed and asked to construct their family genograms. Specific and distinct features were found regarding family configurations, stressful life events and relationship patterns in each group. The implications of the use of the genogram as a research instrument of the impact of stressful events in the family-school transition are discussed.