From diverse perspectives, there is little doubt that depressive symptoms cohere to form a valid and distinct syndrome. Research indicates that an evidence-based assessment of depression would include (a) measures with adequate psychometric properties; (b) adequate coverage of symptoms; (c) adequate coverage of depressed mood, anhedonia, and suicidality; (d) an approach to suicidality that distinguishes between resolved plans and preparations and desire and ideation; (e) assessment of the atypical, seasonal, and melancholic subtypes; (f) parameters of course and chronicity; and (g) comorbidity and bipolarity. These complexities need to be accounted for when certain assessment approaches are preferred, and when ambiguity exists regarding the categorical versus dimensional nature of depression, and whether and when clinician ratings outperform self-report. The authors conclude that no one extant procedure is ideal and suggest that the combination of certain interviews and self-report scales represents the state of the art for evidence-based assessment of depression.