One of the earliest transitions that children in the United States experience is the transition to formal schooling, which for many children begins with kindergarten at about 5 years of age. This transition is a big change for young children, and teachers and parents alike commonly discuss how challenging it can be for some children. However, there is little evidence on how common these challenges actually are and which children are most likely to experience them. To understand the occurrence of these problems, we asked 45 kindergarten teachers in central Ohio to complete a transition difficulty questionnaire on 688 students in the fall of their kindergarten year. Results showed that 72% of children experienced at least one of five difficulties during the transition. The most common difficulties reported were related to meeting the academic demands of kindergarten and staying organized. However, we also found that difficulties co-occurred; children typically either experienced no difficulties or all of the difficulties measured. Finally, we also found that boys and children with individualized education plans (IEPs) were more likely to experience difficulties during the transition. (author abstract)