The cross-cultural validity of the Child Behavior Checklist for Ages 2-3 (CBCL/2-3) was tested in three Dutch samples of children referred to mental health services, from the general population, and from a twin study. Six scales were derived from factor analyses and labeled Oppositional, Aggressive, and Overactive, which constituted a broadband Externalizing grouping; Withdrawn/Depressed and Anxious, which constituted a broadband Internalizing grouping; and Sleep Problems. Internal consistencies of the scales, their test-retest reliabilities, interparent agreement, discriminative power, predictive relations with problem ratings 2 years later, and relations to other instruments designed to measure general development and behavior problems were adequate, and highly comparable to psychometric properties in American samples. It was concluded that across languages and cultures behavioral/emotional problems of young preschoolers may be adequately assessed with the CBCL/2-3.