We provide the first validation data on the Strengths and Difficulties Questionnaire (SDQ3-4), a brief screening tool for behavioral and emotional problems, in preschool children. Parents of a community sample of 1341 Spanish 3-year-olds and teachers of a sample of 622 children responded to the SDQ3-4 and different measures of psychopathology. Confirmatory factor analysis yielded adequate fit of the model to the original structure. Internal consistency (omega coefficient) for total scores was.87 for parents and.91 for teachers. Convergent validity of SDQ3-4-parents' reports with Achenbach's taxonomy and diagnostic interview was good, but low for SDQ 3-4-teachers' reports. The SDQ3-4 showed predictive accuracy for discriminating use of mental health services and functional impairment. This is the first work presenting empirical evidence of the reliability and validity of the parents' and teachers' SDQ3-4 for preschoolers. The SDQ3-4 presents acceptable psychometric properties for use in the identification of preschool children who might have behavioral or emotional problems. © 2013 Elsevier Inc.