Previous research indicates that children who spend many hours in early child care exhibit more externalizing behavior problems than children who spend less time in child care. Concern has been expressed regarding the cumulative effect of these problem behaviors on elementary school classes. We collected information about children's child-care histories from parents of first through fourth graders ("N" = 429) and about classroom functioning from their teachers ("N" = 31). We analyzed associations between the proportion of children in the class who had spent many hours in care prior to school entry and teachers' reports of the time they spent in instruction and management, the difficulty they had in teaching and managing the class and the frequency of students' positive and negative behavior in the classroom. No significant associations were found to support the contention that prior child-care participation negatively affects classroom functioning.