International comparisons were conducted of preschool children's behavioral and emotional problems as reported on the Child Behavior Checklist for Ages 1 1/2-5 by parents in 24 societies (N = 19,850). Item ratings were aggregated into scores on syndromes; "Diagnostic and Statistical Manual of Mental Disorders"-oriented scales; a Stress Problems scale; and Internalizing, Externalizing, and Total Problems scales. Effect sizes for scale score differences among the 24 societies ranged from small to medium (3-12%). Although societies differed greatly in language, culture, and other characteristics, Total Problems scores for 18 of the 24 societies were within 7.1 points of the omnicultural mean of 33.3 (on a scale of 0-198). Gender and age differences, as well as gender and age interactions with society, were all very small (effect sizes less than 1%). Across all pairs of societies, correlations between mean item ratings averaged 0.78, and correlations between internal consistency alphas for the scales averaged 0.92, indicating that the rank orders of mean item ratings and internal consistencies of scales were very similar across diverse societies. (Contains 4 tables and 1 figure.)