Anxiety and depression in children and adolescents are reviewed, including differential diagnosis, assessment of symptoms, family history data, developmental features, and clinical correlates. Findings indicate that 15.9% to 61.9% of children identified as anxious or depressed have comorbid anxiety and depressive disorders and that measures of anxiety and depression are highly correlated. Family history data are inconclusive. Differences emerged among children with anxiety, depression, or both disorders. Anxious children were distinguishable from the other 2 groups in that they showed less depressive symptomatology and tended to be younger. The concurrently depressed and anxious group tended to be older and more symptomatic. In this group, the anxiety symptoms tended to predate the depressive symptoms. Findings are discussed in the context of a proposed developmental sequence.