In a longitudinal study we tested how well developmental and behavior problems in first-grade students were predicted by preschool screening. Preschool teachers had screened 221 six-year-olds and 159 five-year-olds with the Dortmunder Entwicklungsscreening fur den Kindergarten (DESK 3 - 6; Troster, Mender & Reineke, 2004) and the Verhaltensbeurteilungsbogen fur Vorschulkinder (VBV 3 - 6; Dopfner, Berner, Fleischmann & Schmidt, 1993). We tested whether children revealed developmental and behavior problems in their school readiness examinations had already been detected at preschool. Results showed that the majority of children with developmental problems at the school readiness examination (learning-related problems, motor problems, speech disorders) had been detected by the preschool screening. However, behavior problems diagnosed at the school readiness examination were not predicted by the preschool screening. Whereas most children with later developmental problems were detected by the preschool screening, many children detected in this screening had become problem-free by the time of the school readiness examination. It is concluded that this is because the screening procedures tap into broad areas of development and behavior that are significant for successful learning at school but not included in the school readiness examinations.