Depending on the population of children examined, 2-50 percent of children and adolescents can be diagnosed as exhibiting clinical symptoms associated with depression. Controversy exists as to how depression is expressed at various age levels, its relationship to other forms of psychopathology, differences in ratings based on setting or informant, and measures most likely to provide accurate diagnostic information. Assessment issues related to the purpose of evaluation, treatment and use of these procedures are addressed. Moreover, this article reviews the current self-rating scales, interviews, parent, teacher and peer rating scales most often employed in clinical assessment of childhood depression. Psychometric properties are discussed, particularly those related to reliability and validity (sensitivity, specificity, positive predictive value, negative predictive value and classification accuracy).