This article examined teachers’ judgments of the prevalence and types of problems children present upon entering kindergarten. A large, national sample of teachers ( N = 3,595) was surveyed by using the National Center for Early Development and Learning’s Transition Practices Survey (1996) . Teachers reported they perceived that 16% of children had difficult entries into kindergarten. Up to 46% of teachers reported that half their class or more had specific problems in any of a number of areas in kindergarten transition. Rates of perceived problems were related to school minority composition; district poverty level; and, for certain behaviors, school metropolitan status. The effects of these demographic characteristics were independent and additive. Teachers’ ethnicity showed a significant relation to their rates of reported problems. Results are discussed in terms of risk factors that predict transition problems and the match between children’s competencies and teacher’s expectations. These findings confirm the view that entering kindergarten is indeed a period of transition for children.