Early identification of social-emotional behavioral problems in infants and preschoolers is critical. Nine parent-report and caregiver/teacher-report instruments measuring preschool social-emotional behavioral problems and strengths are reviewed. Advantages to the use of parent-report and caregiver/teacher-report instruments are that they are easy to administer, are inexpensive, and can be used for repeated administration to monitor treatment effectiveness. Reviewed instruments varied in their assessment domains and psychometric properties. Practitioners and researchers must choose the instrument that fits their purposes and psychometric qualifications. In addition, special attention should be given to an instrument's cultural sensitivity. Given the relatively low reliabilities and validities of most of the instruments, it is suggested that these measures be used as screening measures rather than as clinical tools and that they be used alongside other assessment methods. Multidimensional assessment is encouraged.